1 cup (125 grams) all-purpose flour
1 teaspoon (5 grams) baking powder (the aluminum-free kind, if you can find it)
Large pinch of salt
1 cup (200 grams) granulated sugar plus 1 to 2 tablespoons (depending on sweetness of plums)
1/2 cup (115 grams or 8 tablespoons) unsalted butter, softened
2 large eggs
12 smallish plums, halved and pitted
2 teaspoons (10 ml) fresh lemon juice
1 teaspoon ground cinnamon
Heat oven to 350°F
Halve the plums, remove pits and set aside.
Sift or whisk together flour, baking powder and salt in a medium bowl. In a larger bowl, cream butter and 1 cup sugar together with an electric mixer until fluffy and light in color. Add the eggs, one at a time and scraping down the bowl, then the dry ingredients, mixing until just combined.
Spoon the batter into a greased 8 inch springform pan. Any other 8 or 9 inch pan works as well, you just won’t be able to take the whole cake out and present it on a platter. Place the plum halves, skin side up, on top of the batter squishing in as many as fit in a single layer without overlapping. Sprinkle evenly with cinnamon and lemon juice, then sprinkle with 2 tablespoons sugar.
Bake until cake is golden and a toothpick inserted into a center part of the cake comes out free of batter (but of course not plum juice), about 45 to 55 minutes, starting to check for doneness after 45 minutes. This will depend on how big your pan is, as a smaller pan will have thicker batter and will take a few extra minutes to bake. Remove and cool before serving, or you can refrigerate or freeze it until you’re ready to serve.
Once cool, if you can stand it, and I highly recommend trying, leave it covered at room temperature overnight. This cake is even better on the second day, when those juicy plums have had enough time to soak into the cake around them.
Sprinkle with icing sugar and whipped cream for a beautiful presentation and a little extra sweetness.
If serving from frozen, reheat briefly in the oven at 300°F