01 -
Preheat the oven to 350°F. Generously butter an 8 or 9-inch round cake pan to prevent sticking.
02 -
Pour melted butter into the bottom of the prepared cake pan. Sprinkle brown sugar evenly over the butter. Distribute sliced strawberries and chopped rhubarb on top of the sugar in an even layer.
03 -
In a large bowl, cream together room-temperature unsalted butter and granulated sugar until light and fluffy. Add the egg and vanilla extract, beating until incorporated.
04 -
In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, and salt.
05 -
Gradually add dry ingredient mixture to the creamed butter mixture, alternating with buttermilk. Mix until just combined and batter is smooth.
06 -
Gently spread the batter evenly over the fruit in the cake pan. Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean.
07 -
Remove from oven and allow the cake to cool in the pan for 5 minutes. Run a knife around the edge and carefully invert onto a serving plate. Let cool completely.
08 -
Slice when cool and serve with whipped cream.