For the topping:
1 1/3 cup flour
1 teaspoon baking powder
3 tablespoons sugar
3 tablespoons Demerara sugar (or Sugar in the Raw)
Zest of 1/2 a lemon (optional - you can replace this vanilla bean)
1/4 pound (1 stick or 4 ounces) unsalted butter, melted
For the filling:
1. Heat oven to 375°F. In a mixing bowl, combine flour, baking powder, sugars and lemon zest and add the melted butter. Mix with a spatula, then your hands, until small and large clumps form. Refrigerate.
2. In the meantime, prepare filling: Toss strawberries, lemon juice, sugar, cornstarch and a pinch of salt in a 9-inch deep-dish pie plate, or something similar. (I used an oval dish, because it looks slightly more presentable.)3. Remove topping from refrigerator and cover fruit thickly and evenly with topping.
4. Place pie plate on a foil-lined baking sheet, and bake until crumble topping is golden brown in places and fruit is bubbling beneath, about 40 to 50 minutes. Serve warm with (what else?!) ... ice-cream!