Strawberry-Rhubarb Upside-Down Cake

We won’t blame you if the number one reason for baking this cake is for that gorgeous crosshatch rhubarb design. After all, it’s probably the prettiest recipe for your precious spring rhubarb. But you’ll be happy to learn that while this strawberry-rhubarb upside-down cake is stunning to look at, it’s just as delicious to eat.

Like a pineapple upside-down cake, the rhubarb bakes on the bottom of the pan, where the direct heat concentrates its flavor. The rhubarb slowly bakes into the strawberry gelatin, setting it up, and mini marshmallows melt over the strawberry-rhubarb layers to adhere them to the tender yellow cake. Once the cake has baked, it is quickly inverted onto a serving tray and any juice running from the strawberry-rhubarb layers soaks into the top of the cake.

Ingredients for Strawberry-Rhubarb Upside-Down Cake

• Rhubarb: To create the crosshatch design, cut the fresh rhubarb into 3-inch pieces. You won’t be able to make the design if you’re using sliced rhubarb, but sliced rhubarb still works and makes a yummy cake. If using frozen rhubarb, allow it to thaw completely, then drain the water without pressing down on the rhubarb.
• Strawberry gelatin: Make sure your strawberry gelatin package indicates that it’s 6 ounces—nothing bigger, nothing smaller. Also, there’s no need to prepare it, as we’re just sprinkling the mix straight into the pan.
• Sugar: The sugar is sprinkled with the gelatin and marshmallows to sweeten the topping. Use granulated sugar, as brown sugar may discolor the topping.
• Miniature marshmallows: With the strawberry gelatin, mini marshmallows add extra stabilization, helping “glue” the rhubarb pieces to the cake. The marshmallows also sweeten things up a bit too.
• Cake mix: While we recommend white or yellow cake mix, feel free to use strawberry cake mix for more strawberry flavor. Or, bake this cake with a gluten-free cake mix if needed.
• Whipped topping: Optionally, serve thawed whipped topping or homemade whipped cream with slices of the cake. Place the cream next to the cake, as it would be a crime to cover up that gorgeous crosshatch!

Directions

Step 1: Create the crosshatch design

Preheat the oven to 350°F. Place the rhubarb in a greased 13×9-inch baking pan.

Editor’s Tip: To create the crosshatch design, lay five to six slices of 3-inch rhubarb vertically in the greased 13×9-inch pan, creating a small square. Place the next five to six slices horizontally. Repeat with the remaining rhubarb in alternating directions until you have 12 squares (the number of squares may depend on rhubarb thickness).

Step 2: Top with the gelatin and marshmallows

Evenly sprinkle the rhubarb with the strawberry gelatin, sugar and mini marshmallows—in that order.

Step 3: Add the cake batter

Prepare the cake mix according to the package’s directions. Evenly pour the cake batter over the mini marshmallows.

Step 4: Bake the cake

Slide the pan into the oven and bake the cake until a toothpick inserted in the center comes out clean, 40 to 45 minutes.

Step 5: Invert and serve

Cool the cake in its pan at room temperature for 10 minutes. Carefully and quickly invert the cake onto a serving plate.

Once the cake has cooled to room temperature, serve slices with whipped topping if desired.

Recipe Variations

• Change the gelatin flavor: Instead of strawberry, feel free to use another gelatin flavor that will still pair with the rhubarb’s flavor and match its color. Raspberry or cherry gelatin would be best. While blueberries and blackberries pair with rhubarb, the gelatin’s color will discolor the rhubarb.
• Bake the cake layer from scratch: You don’t have to use a cake mix for our rhubarb upside-down cake with Jell-O. Most cake recipes will work, so long as the batter can bake in a 13×9-inch pan. For example, our yellow cake recipe would work well for this rhubarb upside-down cake 13×9-inch pan recipe.

How to Store Strawberry-Rhubarb Upside-Down Cake

Once the cake has cooled to room temperature, place the cake back in its pan (rhubarb side up) and cover the top of the pan tightly with storage wrap. Just make sure the storage wrap isn’t touching the rhubarb or the rhubarb might adhere to the wrapping and get pulled off when unwrapped. Or, place slices in an airtight container. Store the cake in the fridge for up to three days.

Can you freeze strawberry-rhubarb upside-down cake?

Yes, you can freeze this strawberry-rhubarb upside-down cake with Jell-O. Allow the cake to cool to room temperature, then place it back in the pan, rhubarb side up. Cover the top of the cake with two layers of storage wrap, making sure the wrap doesn’t touch the rhubarb or it may pull the rhubarb away when you unwrap it. Freeze the cake for up to one month, then thaw it overnight in the fridge.

Strawberry-Rhubarb Upside-Down Cake Tips

How do you make the crosshatch design with the rhubarb?

To make the pretty crosshatch design, cut the rhubarb into 3-inch pieces instead of just slicing them. Lay five to six slices of the rhubarb vertically in a greased 13×9-inch pan, forming a square, then place the next five to six slices horizontally. Repeat this sequence with the remaining rhubarb in opposite directions until you have 12 squares. Keep in mind, the number of rhubarb pieces and squares may depend on the rhubarb’s thickness.

Where can you buy fresh rhubarb?

Rhubarb is usually available to buy fresh only during its harvesting season. From early to late spring, look for rhubarb in your local grocery store or farmers market.

Why is my cake not baking through?

Your cake may not be baking completely if you didn’t thaw the frozen rhubarb. If using frozen rhubarb, allow it to thaw completely, then drain the excess liquid. Frozen fruits and veggies expel a lot of water when thawed, which could add too much moisture to your cake, causing it to not bake through properly.

What do you serve with strawberry-rhubarb upside-down cake?

Besides the whipped topping, serve strawberry-rhubarb upside-down cake with a scoop of vanilla ice cream. Fresh or macerated strawberries would be excellent here too. Or, heighten the strawberry-rhubarb flavor even more with our strawberry-rhubarb sauce.