Rhubarb Upside Down Cake

A retro classic, updated with rhubarb.

Fruit:

2 c fresh rhubarb, sliced into 1⁄2” cubes
1⁄2 c granulated sugar
2 t cornstarch
1⁄2 c brown sugar
4 T unsalted butter

Cake:

1 1⁄2 c cake flour
1⁄4 t kosher salt
2 t baking powder
1⁄2 c unsalted butter, soft room temperature
3⁄4 c sugar
2 eggs
2 t vanilla
Zest of half a lemon
1⁄2 c sour cream
Vanilla ice cream or whipped cream for serving

Preheat oven to 325 degrees. Butter a 9x9 baking pan and line the bottom with a sheet of parchment. Butter the parchment.

Toss rhubarb in a medium bowl with 1⁄2 cup granulated sugar and cornstarch. Set aside.

In a small skillet, combine the brown sugar and 4 tablespoons butter. Cook over medium heat until the butter and sugar have melted, about 2 minutes.

Sift the flour, salt, and baking powder into a medium bowl. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, about 3 minutes. Add eggs one at a time, beating well after each addition and scraping down the sides of the bowl as needed. Mix in the vanilla, lemon zest, and sour cream. Turn mixer to low and add the dry ingredients in two additions. Mix until just combined, don’t over mix.

Pour the brown sugar mixture into the prepared pan and add rhubarb and any juices. Dollop batter over fruit and smooth with an offset spatula. Bake for 40-45 minutes, until cake is golden and a cake tester inserted into the middle comes out with only a few crumbs attached. Remove the pan from the oven and allow to cool 10 minutes. Place a large serving platter over the pan and carefully invert the pan over the platter. Serve warm with vanilla ice cream or whipped cream.