The plums are definitely prune plums, as evident once they're baked! (I loved the chapter in Molly Wizenberg's book " A Homemade Life" about her father stewing prunes. I also remember my Mom doing the same thing!).
The cake, or pflaumenkuchen, it's German name, is light and tender with a wonderful hint of lemon from the zest added to the batter. Although I totally forgot to brush the top with melted butter and sprinkle with sugar and cinnamon, the cake was delicious! Also, I didn't have any whipped cream in the house, that would have made this homey lightly sweet cake just that much better!
I halved the recipe ( because I didn't buy enough plums!) and baked mine in an 8" square pan.
Start by mixing the dry ingredients in a small bowl.
Add the sugar and beat for 2 to 3 minutes on medium speed til fluffy.
Add the lemon zest and egg and beat in well.
Add the flour mixture alternately with the milk.
Brush with melted butter and sprinkle the top with sugar and cinnamon mixture. ( Remember this step!)
1 1/2 cups unbleached AP flour
1 tsp. baking powder
6 tbsp. unsalted butter, room temp.
1/3 cup granulated sugar
Finely grated zest of 1 lemon
1 large egg
1/3 cup whole milk
2 lbs. Italian prune plums ( about 21), halved and pitted
2 tbsp. unsalted butter, melted
1/3 cup granulated sugar
1/2 tsp. cinnamon
Preheat oven to 400. Position rack to center of oven. Butter a 13" x 9" x 2" baking pan ( do not use cooking spray).
1. In a medium bowl, whisk the flour and baking powder. Set aside.
2. In another bowl, using a hand held electric mixer, beat the butter til smooth.
3. Add the sugar and beat for 2 to 3 minutes on medium speed, til fluffy.
4. Add the lemon zest and egg and beat in well.
5. On low speed, alternately add the flour mixture in 3 additions and the milk in 2 additions, beginning and ending with the flour, beating only til smooth after each.
6. Place tablespoon sized gobs of the batter over the bottom of your prepared pan. Lightly butter your fingers ( I found slightly dampened fingers worked better) and pat the batter into an even layer covering the pan bottom.
7. Arrange the plums, skin side up in tightly packed rows on top of the batter.
8. Brush with the melted butter and sprinkle the cinnamon/sugar mixture evenly over the plums.
9. Bake 35 to 40 minutes, until the plum juices bubble very slowly and a toothpick inserted into the cake comes out clean.
10. Cool kuchen in the pan on a wire rack and serve warm, with dollop of whipped cream if desired.