Prune plums are not my favorite fruit; they're dull eaten out of hand. And their appearance in the market means that summer is coming to an end.
Bake them into this torte, however, and they come into their own. Because they're firm, rather than juicy, they maintain their integrity, becoming soft little pillows of sweetness surrounded by cake. I don't know a better coffee cake.
Plum Torte
1 stick (4 oz.) unsalted butter, softened
1/2 cup sugar
2 eggs, room temperature
3/4 cup buttermilk or plain yogurt
1/2 teaspoon vanilla
zest of one lemon
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon salt
1/2 teaspoon baking soda
12 large or 20 small prune plums, pits removed, halved the long way
4 tablespoons brown sugar, divided
Heat an oven to 350 degrees
Prepare a 9” round cake pan. (If you don't have a commercial pan with high sides, best to use a larger pan, or a springform pan.) Butter the bottom and sides of the pan, and line the bottom with parchment paper. Butter the parchment paper and dust the whole pan with flour.
Cream the butter with the sugar until light and fluffy in a stand mixer for about 5 minutes.
Add the eggs one at a time and thoroughly combine after each addition. If the batter appears curdled, do not worry, it is because the eggs may be cooler than the rest of the mixture, and the butter hardened when the eggs were added. The batter will become smooth with the addition of the flour..
Beat in the the buttermilk or yogurt and add the vanilla and lemon zest, medium speed
Whisk together the flour, the baking powder, baking soda and salt, and add to the butter mixture until just combined.
Separate the halved plums into two equal piles.
Spoon half the batter into the pan and level the top with a small offset spatula.
Place the plums, cut side down on the batter, and sprinkle with the two tablespoons brown sugar.
Spoon the rest of the mixture over the plums, and place the rest of the plums on top cut side up. Sprinkle with the remaining brown sugar.
Bake for 50-60 minutes until golden.
Cool the cake on a rack for 5 minutes. The cake will pull away from the sides of the pan.
Run a knife around the edge of the cake. Invert onto a plate, peel away the paper, and invert again onto a serving plate.
Best served warm with billows of whipped cream - but delicious at any temperature.