Raspberry Strawberry Crumble Tarts with Pecan Streusel

Steps

1. Make the crust: whisk 300 g of the flour, 15 g of the granulated sugar and 4 g of the salt in a large bowl. Cut in 200 g of the cold butter until the pieces are pea- to almond-sized.
2. Drizzle in the ice-cold water a little at a time, tossing with a fork until the dough just holds together when squeezed. Divide it in half, flatten into two disks, wrap and chill for 1 hour.
3. Make the crumble while the dough chills: mix the remaining 90 g of flour with the oats, brown sugar, pecans, cinnamon and the remaining 1 g of salt. Rub in the remaining 85 g of butter with your fingers until clumpy, then refrigerate.
4. Roll each dough disk into an 11-inch round and fit into two 9-inch pie or tart pans, trimming and crimping the edges. Chill the shells for 20 minutes. Set a rack in the lower third of the oven and preheat to 400°F (200°C).
5. Make the filling just before baking: in a large bowl stir the remaining 135 g of granulated sugar with the cornstarch and lemon zest, then gently fold in the raspberries, strawberries, lemon juice and vanilla.
6. Divide the filling evenly between the chilled shells, then scatter half of the crumble over each tart.
7. Set the tarts on a rimmed baking sheet and bake for 20 minutes, then lower the oven to 375°F (190°C) and bake 30 to 35 minutes more, until the crust and crumble are deep golden and the filling bubbles thickly in the center. Tent with foil if the crumble browns too fast.
8. Cool the tarts on a rack for at least 3 hours so the filling sets, then cut each into 6 slices.