Almond and Plum Snack Cake

Preheat the oven to 350 degrees. Combine 1 ½ cups sugar, butter, ½ cup almond paste, baking powder, salt and lemon zest in the bowl of a food processor. Process until light, creamy and smooth, about 45 seconds. With the processor running, add eggs, one at a time, incorporating fully after each addition. Mixture should look thick and fluffy. Add the sour cream, and process until fully incorporated, about 30 seconds, stopping to scrape the bowl as needed. 

Whisk together the cake flour and all-purpose flour in a large bowl. Add the sugar mixture to the flour mixture; whisk just until all dry ingredients are incorporated. Using a rubber spatula, fold the batter to thoroughly combine ingredients.

Toss together the plums and lemon juice in a medium bowl; let stand 5 minutes. Line a 13-by-9-inch baking pan with parchment paper; lightly grease with cooking spray. Spread batter in the prepared pan, smoothing it with an offset spatula. Sprinkle remaining crumbled almond paste over batter. Arrange plums over top, and sprinkle with almonds and remaining 2 tablespoons sugar.

Bake the cake until lightly browned and a wooden pick inserted into the center comes out clean, 45 to 50 minutes. Transfer the cake in the pan to a wire rack, and let cool completely, about 2 hours.