Ingredients
12 tablespoons (1 1/2 sticks) unsalted butter, softened, plus more for pan
2 1/2 cups all-purpose flour, plus more for dusting
2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt
1 1/4 cups granulated sugar
3 large eggs, lightly beaten
1 1/2 cups sour cream
12 ounces Italian prune plums or other plums, cut into 1/2-inch pieces
4 teaspoons pure vanilla extract
1 1/2 cups all-purpose flour
12 tablespoons (1 1/2 sticks) unsalted butter, softened
3/4 cup confectioners' sugar, plus more for dusting
1/4 teaspoon salt
3 tablespoons cold unsalted butter
1/2 cup packed dark-brown sugar
1 teaspoon ground canela (Mexican cinnamon) or regular cinnamon
1/2 cup pine nuts, toasted
Pinch of salt
Preparation
Make streusel: Put all streusel ingredients in a bowl. Using a pastry cutter or two knives, blend until mixture resembles coarse meal. Refrigerate.
Make crumb topping: Put all topping ingredients in a bowl. Using a pastry cutter or two knives, blend until mixture resembles coarse meal. Refrigerate.
Make cake: Preheat oven to 375 degrees. Butter and flour a 10-inch tube pan. Sift flour, baking powder, baking soda, and salt together into a medium bowl; set aside.
Put butter and granulated sugar in the bowl of an electric mixer fitted with the paddle attachment. Cream on medium-high speed until pale and fluffy, 2 to 3 minutes. Add beaten eggs in two batches, mixing well. Mix in one-third of flour mixture. Mix in half of sour cream. Repeat with remaining flour and sour cream. Stir in plums by hand.
Pour half of the batter into prepared pan; sprinkle with streusel. Top with remaining batter. Pour vanilla on top. Bake 20 minutes. Sprinkle with crumb topping; bake until golden brown, 25 to 30 minutes more. Let cool on a wire rack. Unmold. Dust with confectioners’ sugar.
