- For the crumble
- 2 cups all-purpose flour
- ¼ teaspoon fine salt
- ¾ teaspoon baking powder
- ¾ cup white sugar
- ¾ cup frozen unsalted butter, (1-1/2 sticks) grated
- 1-½ teaspoon vanilla extract
- 2 large egg yolks
- 1 to 2 teaspoons apple cider vinegar, or enough for dough to "clump"
- For the fruit mixture
- 3 cups fresh berries, (generous cups)
- 2 teaspoons lemon zest
- 4 teaspoons fresh lemon juice
- ⅔ cup white sugar
- 2 to 8 teaspoons cornstarch, depending on how firm you want the fruit filling (I used scant 2 tbsp)
- pinch of cayenne
1. Fruit: In a bowl, stir together berries, lemon juice and zest, sugar, cornstarch, and cayenne. Mix with a spoon. Set aside.
2. Crumble: Whisk together flour, salt, baking powder, and sugar in a mixing bowl. Then grate in the frozen butter. Every quarter stick or so, mix in the butter with a fork, so that the butter pieces get coated with the dry ingredients. Drizzle in vanilla extract and add the egg yolks. Mix with a fork, until the wet ingredients are absorbed. Add the vinegar, and mix with a fork for 30 seconds or so. Then switch to mixing with your fingers - rub everything between your fingertips so everything is combined. If you squeeze it, it should clump together - if it doesn’t, add a little more vinegar or water until it does.
3. Put half the crumble into the casserole. Use something flat to tamp it down until it’s a solid bottom crust. Pour berries over the top, and evenly distribute. Cover them with the rest of the crumble - throw a handful over the top, so that there’s fine crumbs just over the berries, then with each handful, squeeze to clump and then crumble, so that it’s all topped with irregular-sized crumbs.
4. Put into center preheated 350˚ oven and bake for 45 minutes or so, or until top is golden brown and some berry juices have bubbled up through the surface. Allow to cool until just warm or room temperature before serving.