In a large bowl, mix together flour, sugar, and salt. Add the butter and rub it into the flour mixture until it resembles coarse crumbs. Stir in ice water until the dough comes together. Form into a disk, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Filling Preparation

Prepare the Filling

In a bowl, combine the sliced peaches, bourbon, sugar, lemon juice, cornstarch, and lemon thyme. Mix well and set aside to let the flavors meld.

Assemble and Bake

Assemble Tart

Preheat the oven to 375°F (190°C). Roll out the chilled dough on a floured surface and transfer to a tart pan. Trim the excess dough. Pour the peach filling into the crust.

Bake

Bake in the preheated oven for 35-40 minutes, or until the crust is golden and the peaches are bubbly. Let cool slightly.

Mascarpone Topping Preparation

Prepare the Mascarpone Topping

In a mixing bowl, beat the mascarpone cheese with sugar and vanilla extract until smooth. In a separate bowl, whip the heavy cream until soft peaks form. Gently fold the whipped cream into the mascarpone mixture.

Serve

Serve the Tart

Spread the mascarpone topping over the cooled tart and garnish with additional lemon thyme if desired. Slice and serve.