At the farmer’s market last weekend, I came across these really small plums. They are only about the size of a walnut ball, maybe even a little smaller. They were too enticing not to buy. Plum cakes are actually very common in Germany and parts of Eastern Europe, so I thought that minimum, I would make one of my standard plum cakes before I came up with the idea of making an upside down cake. Turned out lovely. All the caramel and toffee bits you see in the photos is where the butter and brown sugar leaked out of my spring form pan (advice : don’t use a spring form pan!). If you can’t find mini-plums, regular ones will work just as well.
About 20 small plums, cut in half and pitted (about 1 inch in diameter)
1/2 cup (1 stick) unsalted butter, melted and divide to 1/4 cup and 1/4 cup
1/2 cup brown sugar
1 tablespoon lemon zest
1 cup full fat buttermilk
2 tablespoons lemon juice
1/2 cup sugar
2 cups all purpose flour
1 teaspoon baking soda
1/4 teaspoon salt
1/4 teaspoon cinnamon
Preheat the oven to 350F. Liberally grease a 9 inch cake pan with 1/4 cup melted butter, or other pan of similar size, with half of the butter. Sprinkle the bottom of the pan with the brown sugar and lemon zest, then add the plums in a single layer, cut side down.
Whisk together the other 1/4 cup melted butter, buttermilk, eggs, sugar, and lemon juice. In a separate bowl, combine the flour, baking soda, salt, and cinnamon. Add the liquid mixture to the flour mixture, and stir gently to combine. Pour the batter into the pan, on top of the plums, smoothing and leveling the top.
Bake for 50-60 minutes, or until a toothpick stuck in the center comes out clean. Let cool for only about 5 minutes. Put a plate that is larger than the pan over the top. Carefully flip the cake over and gently lift the pan off the cake. It’s common for some of the fruit to stick to the pan (but hopefully not!), and you can do a bit of fruit repair and no one will ever know. Let cool at least to room temperature before serving.