Christina's Plum Upside-Down Cake

from Simply Recipes by Elise

Ben does not like fruit desserts, but he requests this over and over! It does need some slightly sweetened whipped cream or heavy cream drizzled on it to cut the tartness a bit.

10 Tbsp butter, softened
1/4 cup brown sugar, firmly packed
4 plums, pitted and sliced
5 Tbsp buttermilk OR 4 Tbsp milk plus 2 teaspoons milk and 1 teaspoon lemon juice
3/4 cup flour
1/2 teaspoon baking powder
1/8 teaspoon baking soda
1/4 teaspoon cinnamon
Pinch salt
1/2 cup granulated sugar
Zest of 1/2 an orange (or one clementine!)
1 egg
1 teaspoon vanilla extract

1 Preheat oven to 350°F. Melt 6 Tbsp of the butter in a deep dish pie plate in the microwave. Add brown sugar and whisk until smooth. Arrange a layer of plum slices on top.
2 If you are not using buttermilk, combine milk and lemon juice in a small bowl (the mixture will curdle), set aside. In a separate bowl, sift together the cake flour, baking powder, baking soda, cinnamon and salt.
3 Use an electric mixer to beat together the remaining 4 Tbsp butter with the granulated sugar and orange zest. Add the eggs and vanilla, mix to combine. Alternately add the dry flour mixture and the buttermilk (or lemon soured milk) mixture to the batter.
4 Pour batter on top of plums. Bake for 50-60 minutes, until cakes are firm to the touch, and a toothpick or skewer inserted in the center does not come out with raw batter on it. (Might be wet from plum juice.)
5 Remove from oven and let cool on a rack until no longer hot to the touch. Run a paring knife around the edges of the pie plate. Invert onto a plate and gently lift off of the plate.

Makes 6-8 individual servings, depending on how you slice it.