Plum Upside Down Cake

Preheat the oven to 350°F: Butter the insides of four 10- or 8-ounce ramekins.

Melt the butter and brown sugar, pour into bottom of ramekins: Melt 3/4 stick (6 tablespoons) of the butter in medium saucepan over medium heat. Add brown sugar and whisk until smooth. Pour into the bottoms of the four buttered ramekins, dividing the sugar butter sauce evenly among them.

Arrange the plum slices: Place the slices at the bottom of each ramekin.

Whisk the dry ingredients for batter: In a separate bowl, vigorously whisk together the cake flour, baking powder, baking soda, cinnamon and salt.

Make the cake batter: Use an electric mixer to beat together the remaining 1/2 stick (1/4 cup or 4 tablespoons) 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.

Bake: Divide the batter among the ramekins. Place the ramekins on a rimmed baking sheet and put in the oven on the middle rack. Bake at 350°F for 35 to 40 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.) Turn the baking sheet around half-way through the baking to ensure an even baking for all the cakes.

Cool and invert: 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 ramekins. Invert onto a plate and gently lift off of the plate. Serve alone or with whipped cream or vanilla ice cream .