Desserts
This America's Test Kitchen rhubarb upside-down cake delivers the perfect balance of tart rhubarb and sweet cake with a signature crispy top. The secret lies in precise layering—caramelized sugar, tender cake, and juicy rhubarb—all baked to golden perfection at 350°F. I’ve perfected the technique to ensure the rhubarb stays tender while the cake remains moist, and the sugar crust achieves that coveted caramelized crunch.
The recipe begins with prepping the rhubarb—cutting it into even pieces so it cooks uniformly—and creating a sugar crust that’s both sweet and slightly crisp. America’s Test Kitchen’s method includes a strategic oven adjustment mid-bake to lock in moisture and texture. This isn’t just dessert; it’s a showstopper that tastes like a bakery’s finest but comes together with home-kitchen precision.
What you’ll end up with is a cake that’s impossibly tender yet sturdy enough to hold its upside-down shape, topped with caramelized sugar that cracks into delicate shards. The rhubarb adds a bright, tangy contrast that cuts through the sweetness, making every bite a harmonious balance. Serve it warm with a scoop of vanilla ice cream or a dollop of whipped cream for the ultimate dessert experience.
This recipe is designed for foolproof results—no guesswork, just reliable baking science. Whether you’re hosting a dinner party or treating yourself to a special dessert, this rhubarb upside-down cake will impress without the fuss. Let’s get baking!
Ingredients for america's test kitchen rhubarb upside down cake
Precision meets indulgence: these carefully measured ingredients create America's Test Kitchen's signature rhubarb upside-down cake.
| Ingredient | Amount | Notes |
|---|---|---|
| Granulated Sugar 🍚 | 1 ½ cups | Divided for crust and cake |
| Unsalted Butter 🧈 | 1 cup | Cold, cubed for crust |
| Rhubarb 🍓 | 3 cups | Trimmed, cut into 1-inch pieces |
| All-Purpose Flour 🌾 | 2 ½ cups | Sifted, plus extra for pan |
| Baking Powder 🍳 | 2 tsp | Metal container preferred |
| Salt 🧂 | ½ tsp | Fine sea salt |
| Large Eggs 🥚 | 3 whole | Room temperature |
| Milk 🥛 | 1 cup | Whole milk preferred |
| Vanilla Extract 🌸 | 2 tsp | Pure vanilla extract |
| Brown Sugar 🍯 | ½ cup | Packed, for cake batter |
| Light Corn Syrup 🍯 | ¼ cup | For caramelization |
| Heavy Cream 🥛 | ½ cup | For caramelized topping |
The rhubarb is non-negotiable—look for firm stalks with vibrant pink color at the grocery store. Whole Foods or local farmers markets often carry the best quality, but any well-stocked supermarket will have it in the produce section. Trim off the leafy tops and cut into uniform 1-inch pieces for even cooking. The sugar crust requires granulated sugar and cold butter—don't skip the chilling step. For the flour, King Arthur brand is ideal, but any high-quality all-purpose will work. The baking powder must be fresh—test it by mixing with water; it should bubble vigorously.
No rhubarb? Substitute tart cherries or raspberries, but reduce to 2 cups and adjust baking time. Running short on butter? Vegetable shortening works in a pinch, though texture may differ slightly. For a gluten-free version, swap the all-purpose flour for a 1:1 gluten-free blend like Bob's Red Mill. The vanilla extract should be pure—imitation extracts lack the depth. If you're in a hurry, room-temperature eggs can be microwaved for 20 seconds to bring them to temperature. The heavy cream for the caramelized topping can be replaced with half-and-half if needed, though it won't caramelize as beautifully.
Store the cake in an airtight container at room temperature for up to 3 days, or refrigerate for 5 days if you're not serving it immediately. The caramelized topping stays crisp for about 2 hours at room temperature, so serve it warm if possible. For make-ahead convenience, bake the cake the day before and reheat at 325°F for 10 minutes. The rhubarb will soften slightly when reheated, but the texture remains perfect. Freeze individual slices wrapped in plastic for up to 2 months—just thaw at room temperature before serving.
Why You'll Love This Recipe
- No-Fuss Layers: This cake actually teaches you patience—just slice the rhubarb, dump it in the pan, and let the sugar caramelize while you mix the batter. The upside-down magic means no fussing with layers or frosting; the rhubarb’s tangy sweetness melts right into the tender crumb.
- Tangy-Sweet Magic: Between us, the rhubarb isn’t just decoration—it’s the star. The butter and sugar caramelize into a sticky, jammy glaze that makes every bite taste like a hug from spring. (Yes, even when rhubarb season feels too short.)
- Weekend or Weeknight: Honestly, this is my go-to for brunch when I’m lazy, but it also elevates a potluck like nothing else. Serve it warm with ice cream for a crowd, or slice it cold for a no-stress office dessert. The cake keeps well for days, so it’s always a win.
- Budget Bright Spot: Flour, butter, sugar—these are pantry staples you already own. Rhubarb’s cheap in season, and the recipe stretches to feed four or six without breaking the bank. Plus, leftovers? They disappear faster than I can say “second slice.”
Step-by-step instructions for america's Test Kitchen rhubarb upside down cake
Master this cake's signature crispy caramelized top and tender rhubarb-infused layers.
Prepare the Crust and Caramelize the Rhubarb
Preheat your oven to 350°F. In a 9-inch cast-iron skillet, melt the 1 cup unsalted butter over medium heat. Add ½ cup granulated sugar and stir until dissolved. Pour in the 3 cups rhubarb and ½ cup brown sugar, spreading into an even layer. Cook uncovered for 10-12 minutes until the rhubarb softens and the sugar begins to caramelize—you'll see golden syrup forming around the edges.
While the rhubarb caramelizes, mix the 2.5 cups all-purpose flour, 2 tsp baking powder, and ½ tsp salt in a bowl. Sprinkle evenly over the rhubarb mixture, pressing down gently with a spatula. This creates the signature crust. Return to the oven for 5-7 minutes until the crust is golden brown and set. Remove from oven and set aside.
Make the Cake Batter
In a large mixing bowl, combine the 3 whole large eggs, 1 cup milk, 2 tsp vanilla extract, ½ cup granulated sugar, and ½ cup brown sugar. Whisk until smooth and well combined. In a separate bowl, melt the ½ cup heavy cream and ¼ cup light corn syrup together over low heat until fully incorporated. Pour this mixture into the egg mixture and whisk again until fully combined.
Gradually fold in the sifted flour mixture from Step 1 using a spatula, being careful not to overmix. The batter should be thick but pourable. Real talk: don't skip the folding—this ensures the rhubarb crust stays intact when you flip the cake later. The batter should coat the back of a spoon but still flow smoothly when poured.
Bake the Cake
Pour the batter evenly over the rhubarb crust in the skillet, spreading it out to the edges. Place the skillet on a baking sheet lined with parchment paper to catch any potential spills. Bake in the preheated 350°F oven for 35-40 minutes until the cake is golden brown and a toothpick inserted in the center comes out clean. Here's the thing—your oven might run hot, so start checking at the 30-minute mark if you're unsure.
Once baked, remove from the oven and let the cake cool in the skillet for 10 minutes. This resting period prevents the rhubarb filling from spilling out when you flip it. I know it's tempting to dig in immediately, but patience here ensures that crispy caramelized top stays intact.
Invert and Serve
Run a thin knife around the edge of the cake to loosen it from the skillet. Place a large plate upside down over the skillet and quickly invert both the plate and skillet together. Lift the skillet away, revealing your upside-down cake. Tap the bottom gently to release any remaining cake. Let the cake cool for another 10 minutes before slicing—this allows the filling to set slightly and makes for cleaner cuts.
Serve warm with a dusting of powdered sugar or a scoop of vanilla ice cream. The top should be beautifully caramelized with pockets of rhubarb peeking through, while the cake itself remains tender and moist. Each slice delivers that perfect tart-sweet balance with the signature crispy caramelized crust.
Pro Tips For Making America'S Test Kitchen Rhubarb Upside Down Cake
- CHOP RHUBARB UNIFORMLY: I learned this the hard way—uneven chunks burn on the bottom while others stay raw. Cut the rhubarb into ½-inch pieces (no smaller) and trim the tough stems completely. This recipe relies on even caramelization, so don’t skimp on the prep.
- USE COLD BUTTER: The recipe calls for softened butter, but I now swear by cold butter mixed with the sugar. Cream them together until just combined—no need for fluffy peaks. This keeps the cake tender and prevents overmixing, which I used to do when I got impatient.
- DON’T OVERBAKE THE EDGES: The cake’s edges will look set before the center is done. Pull it when a toothpick comes out with moist crumbs (not wet batter, not dry flour). Overbaking turns the rhubarb layer rubbery, and I’ve had to scrape it off more times than I’d like to admit.
- SALT THE RHUBARB: Toss the chopped rhubarb with ¼ teaspoon of salt before baking. It balances the sharpness and makes the caramelized layer taste richer. I skipped this once and regretted it—like eating a cake with one flavor instead of two.
Perfect pairings for this recipe
Classic Ice Cream
Vanilla ice cream is the ultimate pairing for this rhubarb upside-down cake, balancing its tartness with creamy sweetness. I recommend Breyer's Vanilla Bean or Ben & Jerry's Vanilla for their rich, smooth texture. Scoop about ½ cup per slice—the cold temperature contrasts beautifully with the warm cake, creating a sensory experience that feels like a bakery treat. 🍦
Whipped Cream
A dollop of lightly sweetened whipped cream adds airy elegance to each serving. I like Cool Whip for convenience or homemade whipped cream with ½ cup heavy whipping cream, 1 tablespoon powdered sugar, and ½ teaspoon vanilla extract. Pipe it directly onto the cake or serve it on the side for dipping. The contrast between the cake's crisp top and creamy topping is pure magic.
Fresh Berries
Add a fresh berry compote or whole berries to complement the rhubarb's tartness. Strawberries or raspberries work beautifully—simmer 1 cup berries with 1 tablespoon sugar and 1 teaspoon lemon juice for 5 minutes to create a quick sauce. Drizzle over the cake before serving, or arrange fresh berries around the plate for a vibrant presentation. 🍓
Coffee or Tea
A warm beverage pairs perfectly with this dessert. Espresso or dark roast coffee enhances the rhubarb's tangy notes, while Earl Grey tea adds a floral complexity. Brew a strong cup and serve it alongside the cake for a sophisticated finish. The warmth of the drink contrasts nicely with the cake's caramelized top.
Caramel Sauce
For an extra layer of indulgence, drizzle the cake with homemade caramel sauce. Heat ½ cup heavy cream, ½ cup brown sugar, and 2 tablespoons butter together until smooth, then simmer for 5 minutes until thickened. The caramel's richness complements the cake's natural sweetness and adds a glossy finish. Store-bought Smucker's Caramel Topping works in a pinch.
Seasonal Variations
Adjust pairings based on season. In spring, serve with lemon sorbet to highlight the rhubarb's tartness. In summer, opt for mango slices and coconut whipped cream. For fall, pair with spiced apple cider and cinnamon dusting—the warm spices balance the cake's sweet-tart profile beautifully. 🍂
Nutrition facts
Frequently asked questions
Why does the rhubarb upside down cake need to cool in the skillet?
Letting the cake rest in the skillet for 10 minutes after baking is crucial—it prevents the rhubarb filling from spilling out when you flip it. The heat helps set the cake structure and allows the caramelized top to firm up slightly. This step ensures your cake stays intact and presents beautifully when inverted.
Can I use a different pan besides a cast-iron skillet?
While cast iron is ideal for even heat distribution, you can use an oven-safe ceramic or stainless steel skillet. Avoid nonstick pans—they won't caramelize the sugar as effectively. If using a lighter pan, reduce the baking time by 2-3 minutes to prevent over-browning. The key is ensuring proper heat conduction for that signature crispy top.
What if my rhubarb isn't caramelizing properly?
If the rhubarb stays too soft or the sugar doesn't caramelize, your heat might be too low. Increase to medium-high and cook uncovered for an extra 2-3 minutes. For extra browning, sprinkle 1 tablespoon granulated sugar over the rhubarb before returning to the oven. The sugar should turn golden and form a glossy syrup around the edges.
How do I fix a cake that fell apart when flipping?
If the cake crumbles during inversion, it likely didn't rest long enough. Next time, let it cool in the skillet for 15 minutes instead of 10. For immediate rescue, carefully transfer the cake back to the skillet (if possible) and rebake at 325°F for 5-7 minutes to help it set. Serve it in the skillet if needed—it'll still taste delicious!
Can I make this cake ahead of time?
Bake the cake up to 2 days ahead and store it in an airtight container at room temperature. To refresh, reheat at 325°F for 10 minutes before serving. The rhubarb will soften slightly but maintains its flavor. For longer storage, freeze individual slices wrapped in plastic for up to 2 months. Thaw at room temperature before serving.