THE PERFECT RATIO OF CRUMB-TO-CAKE CRUMB CAKE

(from Saveur Magazine, slightly adjusted for spring)
 
makes one 9"x 13” cake
 
(Note: I used white-whole wheat flour in the crumb and pistachios because that’s what I had on hand. I also used rhubarb and raspberries in the cake, but the original recipe calls for well drained cranberries)
 
For the crumb-
 
2 cups all-purpose flour
¾ cup rolled oats
1 cup firmly packed brown sugar
¼ cup sugar
2 tsp. ground cinnamon
1 tsp. kosher salt
1 cup plus 2 tablespoons, cool unsalted butter, cut into small cubes (cut the butter and let it sit out to soften slightly)
⅔ cup sliced almonds (or the nuts of your choice)
 
In a large bowl, whisk together the flour, oats, sugars, cinnamon, and salt. Add the butter pieces, rubbing the mixture together with your fingers until it becomes crumbly with some large chunks. Cover and refrigerate until firm, at least half an hour.  (I was short on time and placed it in the freezer while I prepared the cake.)
 
Preheat the oven to 350 degrees F.
 
For the cake-
 
2¼ cups all-purpose flour
½ tsp. baking powder
½ tsp. baking soda
¾ tsp. kosher salt
¾ cup plus 2 tablespoons (7 oz.) unsalted butter, softened, plus addtl. for greasing
1½ cups sugar
3 large eggs, room temperature
1 tsp. vanilla
1 tsp. almond extract
1 cup full-fat sour cream
*       *      *      *      *      *
10 oz. fresh or thawed frozen fruit (it is key to drain the fruit in a strainer and then drain it once again on a double layer of paper towels)
1-2 Tablespoons sugar to toss with the fruit (I used a combination of rhubarb and raspberries which warranted 2 Tablespoons of sugar)
 
In a large bowl, whisk together the flour, baking powder, baking soda, and salt. In the bowl of a standing mixer fitted with the paddle attachment, beat the butter and sugar until fluffy. Scrape down the sides and the bottom of the bowl, then add the eggs, the vanilla and the almond extract. Beat on low until incorporated. With the mixer on low, alternate adding the flour mixture (in three batches) with the sour cream (in two batches), beginning and ending with the flour mixture, and beating just until incorporated.
 
In a medium bowl, toss the well-drained fruit with 1-2 tablespoons of sugar.
 
Lightly butter a 9"x 13” baking pan, line the bottom with parchment paper, (I like to line the sides with strips of parchment, as well) and retrieve the crumb topping from the fridge. Add the nuts to the crumb, tossing to combine.
 
Place the batter in the baking pan, using an offset spatula to spread it evenly; make sure to fill the corners. Sprinkle the fruit (leave any moisture behind) evenly over the batter. (Don’t be tempted to add additional fruit; it will add too much moisture to the cake.) Crumble the topping evenly over the fruit.
 
Bake on the middle rack of the oven until a cake tester or small paring knife inserted into the center of the cake comes out mostly clean, about 1 hour 10 minutes. Remove and let cool completely. For generous servings, cut the cake in 3¼” x 3½” slices. Wrap any leftovers in plastic wrap.