THE ULTIMATE BERRY CRUMBLE

For Filling
1 cup blueberries
1 cup raspberries
1 cup blackberries
⅓ cup sugar
1 tsp. lemon zest
2 tsp. fresh lemon juice
2 tsp. cornstarch
Pinch cayenne pepper (optional)
For Crumble
2 cups flour
¾ cup sugar
¾ tsp. baking powder
¼ tsp. fine salt
¾ cup unsalted butter, frozen
1½ tsp. vanilla extract
2 large egg yolks
1 to 2 tsp. cider vinegar

Make Filling

1. Preheat oven to 375°F.

2. Stir together blueberries, raspberries, and blackberries in a bowl. Add sugar, lemon zest, lemon juice, cornstarch, and cayenne (if using). Mix until sugar and cornstarch are mostly dissolved.

Make Crumble

3. Whisk together flour, sugar, baking powder, and salt in a bowl until thoroughly combined. Using a coarse shredder, grate frozen butter, stopping occasionally to toss shredded butter into flour mixture to coat. Drizzle in vanilla; add egg yolks. Stir with a fork until egg is mostly absorbed. Add 1 tsp. vinegar; mix briefly. Use your hands to finish mixing, squeezing until clumps form but mixture remains mostly dry. Add 1 tsp. additional vinegar if needed to moisten.

4. Spoon about half of crumble into a 2-qt. baking dish. Press down using a flat-bottom cup until well compacted. Spoon and spread filling on top of crumble. Sprinkle remaining crumble over filling, squeezing some into clumps.

5. Bake until top is well browned and filling is bubbly, 40 to 45 minutes. Let cool to room temperature, about 30 minutes. If desired, serve with whipped cream.