Instructions

1. Heat over to 350°F. Sift or whisk together flour, baking powder and salt in a medium bowl. In a larger bowl, cream butter and 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.
2. Spoon batter into an ungreased 9-inch springform pan (but if you’re worried, you can always lightly coat it first with butter or a nonstick spray) and smooth the top. Arrange the plums, skin side up, all over the batter, covering it. Sprinkle the top with lemon juice, then cinnamon, then remaining sugar.
3. 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 50 minutes. Cool on rack.