Berry Crumble Delight

Collect all the necessary components for preparation.

Preheat your oven to a temperature of 375 degrees Fahrenheit (or 190 degrees Celsius).

Prepare the crumble mixture: In a large container, blend together flour, sugar, baking powder, and salt until they are fully incorporated. Use a whisk to ensure everything is well combined. Incorporate frozen butter into the mixture, periodically stirring it in until the butter is evenly coated with flour.

Combine egg yolks and vanilla using a fork, stirring until the egg is mostly absorbed into the mixture. Add 1 teaspoon of vinegar and mix briefly, ensuring the ingredients are well combined. Use your hands to further blend the mixture, applying pressure until clumps form but the mixture remains mostly dry. If necessary, add more vinegar to achieve the desired consistency. Set the crumble mixture aside for later use.

Prepare the filling: In another large container, combine blueberries, raspberries, and blackberries. Add sugar, cornstarch, lemon juice, lemon zest, and cayenne pepper to the mixture. Stir until everything is well combined and the sugar has mostly dissolved.

Fill a 2-quart baking dish with about half of the crumble mixture, pressing it down firmly using a flat utensil until it is compactly packed. Spread the berry filling on top of the crumble mixture, leaving a small border around the edges. Sprinkle the remaining crumble mixture over the berries, applying pressure to form clumps.

Place the prepared dish in a preheated oven and bake until the top is beautifully browned and the berry filling bubbles, taking approximately 40 to 45 minutes. Allow the dish to cool to room temperature before serving, which should take around 30 minutes.