In a mixing bowl, cream 113g of unsalted butter with 55g of powdered sugar until light and fluffy. Beat in one large egg until fully incorporated.

In a separate bowl, whisk together 135g all-purpose flour, 30g cake flour, and 1/4 tsp kosher salt. Gradually mix the dry ingredients into the wet mixture until just blended.

If the dough is sticky, chill it in the refrigerator for 30 minutes, then roll it out into a 12-inch circle. Fit into a tart pan and freeze for 1 hour.

While the crust is chilling, prepare the filling by slicing 250g of rhubarb and quartering 250g of strawberries. Combine the fruit with 75g of sugar and 1 tsp of vanilla bean paste.

Let the mixture sit for 30 minutes, then strain the fruit to remove excess juices for perfect filling consistency.

In a medium bowl, mix 50g of granulated sugar with 75g of all-purpose flour. Add 27g of melted unsalted butter and stir until the mixture resembles coarse crumbs.

Preheat your oven to 375°F (190°C). Once the crust has been frozen for an hour, layer the rhubarb and strawberry filling into the tart shell.

Scatter 4 oz of fresh raspberries on top, sprinkle with granulated sugar and the crumb topping. Bake for 35-45 minutes, or until the crust is golden.

Allow the tart to cool for 1-2 hours on a wire rack for better serving.