In a large bowl, combine the all purpose flour, almond flour, kosher salt, and powdered sugar. Use a whisk to ensure everything is evenly mixed. The goal is to create a dry mixture that will serve as the foundation of your tart. A light and fluffy blend will lead to a tender crust, so mix well.
Add the chilled unsalted butter pieces to the flour mixture. With your fingers or a pastry cutter, work the butter into the flour until it resembles coarse crumbs. You should see small pieces of butter throughout, which will create that flaky texture we love in a tart crust.
In a separate small bowl, whisk together the egg yolk and 1 tablespoon of cold water. Once combined, pour this mixture into the flour and butter blend. Using your fingers, mix everything together until it starts to come together. If the mixture feels too dry, add another tablespoon of cold water to help it bind.
Once the dough holds together when pinched, transfer it to a buttered tart pan with a removable bottom. If you prefer individual tarts, you can use small tart pans instead. Press the dough evenly into the bottom and up the sides of the pan, ensuring a uniform thickness.
Using a fork, prick the bottom of the crust to prevent it from puffing up while baking. Cover with plastic wrap and refrigerate for about an hour. This step is crucial as it helps the butter firm up, resulting in a crispier crust.
Preheat your oven to 375 degrees Fahrenheit. Once heated, remove the tart crust from the refrigerator and bake for 12 to 15 minutes, or until the edges are golden brown. Keep an eye on the tart towards the end of the baking time to avoid over-browning.
Once baked, allow the crust to cool completely before filling it with the mascarpone mixture. This will ensure that the filling doesn’t melt into the crust and maintains its structure.
While the crust cools, prepare the filling by whipping the whipping cream in a bowl using a hand mixer or stand mixer until soft peaks form. This step adds a light and airy texture to your filling.
Add the room temperature mascarpone cheese and the powdered sugar into the whipped cream. Beat on a medium speed until just combined, being careful not to over-mix, as it can cause the mixture to become too runny.
Once combined, gently fold in the lemon curd with a wooden spoon. The goal here is to keep it fluffy while ensuring that the lemon flavor is evenly distributed throughout the filling.
In a separate bowl, mix the raspberries and sliced strawberries together. To glaze the berries, heat the strawberry preserves in a small saucepan until thinned. This will make it easier to mix with the fresh berries.
Spoon the mascarpone filling into the cooled tart crust, spreading it evenly. Top with the mixed berries and drizzle the warmed strawberry preserves over the top. This not only adds flavor but gives a beautiful shine to the tart. Garnish with fresh mint leaves for a lovely finishing touch.
