PORTLAND, Maine — Preheat oven to 350 degrees F
Coat a 9 by 13-inch baking dish with cooking spray and line the bottom with parchment paper (spray the top of the parchment paper as well – covering both sides).
- 1 box Yellow Cake Mix
- 1/2 cup Vegetable Oil 3 Eggs
- 2 cups Rhubarb, chopped in ½ inch pieces
- 2 cups frozen sliced Strawberries – thawed in their juice
- 2 cups fresh whole Strawberries
- 1/2 stick Butter
- 1/2 cup Brown sugar
- 1 cup heavy Whipping Cream
- 1/2 teaspoon Vanilla
- 2 tablespoons Confectioner’s Sugar
Start by slicing the fresh strawberries lengthwise into 1/4 inch slices and laying them neatly on the parchment paper in the bottom to the baking dish. You could use your artistic flare here to make a pretty design as this will become the TOP of the cake after it is flipped over.
Make a strawberry-rhubarb sauce by melting the butter in a medium sauce pan, then adding the two cups rhubarb with the ½ cup brown sugar. Bring to a simmer, mixing constantly. It may seem that this needs some liquid, but be patient and the rhubarb will give off juice in about one minute. When the rhubarb is tender (after about 4 minutes), add the 2 cups of thawed, sliced strawberries (with the juice) and simmer for another two minutes. The sauce should be thick with big chunks of fruit and liquid.
Using a slotted spoon, transfer the chunks of strawberries and rhubarb from the saucepan and spread them over the slices of strawberry in the bottom of the baking dish. Try not to disturb the sliced strawberries.
After you’ve strained out the chunks, there should be a half cup or so of liquid remaining in the pan. Pour it into a measuring cup and top with enough water to bring it to one cup of liquid total. Stir gently to mix.
Mix the cake mix with the ½ cup oil, 3 eggs, and the 1 cup of strawberry “juice” (from the sauce). (The sauce replaces the water in the recipe on the box.)
Pour the batter into the 9 by 13 pan over the strawberry/rhubarb sauce. Use a spoon or rubber spatula to make sure the surface is fairly level.
Place the cake in the center of the oven and bake at 350 degrees for 30-35 minutes. Test for doneness with a toothpick inserted in the center after 30 minutes.
When the toothpick comes out clean, remove from the oven and set on a rack to cool for at least 20 minutes – up to several hours. Cake can be refrigerated and served the next day. Wait to invert until time to serve.
To prep for inverting the cake, run a thin knife-blade around the edge and jiggle the cake a bit to loosen it. Place a sheet pan upside down over the cake and carefully but quickly flip the cake over holding tightly to the edges of the sheet pan and the cake pan at the same time. If the cake doesn’t “drop” out of the pan onto the sheet pan, you can gently tap the bottom or try lifting the cake pan and dropping it from about an inch high to get the cake out. Then lift the cake pan off the cake and slowly remove the parchment paper.
Whip the cream with the vanilla and confectioner’s sugar, and serve a dollop on the cake. Enjoy warm or cold! This cake freezes well.
Chef’s note – we usually freeze our rhubarb to be used in the winter when we have more time for cooking and baking. This recipe can be made with frozen rhubarb as well as the frozen strawberries. You can usually find fresh berries to slice at the grocery store year-round, or you can forego that step and just use the frozen. It is delicious both ways!