In a food processor, combine the dry cookie ingredients and pulse until combine. Add in the cold butter and pulse again until it looks like course cornmeal. Add in the vanilla and the egg and mix until the dough is smooth and cohesive.

Press the filling into a greased tart pan or pie plate using a rubber spatula. Make sue the dough is evenly spread and lightly goes up the sides. Bake in a preheat 350 degree oven for 12-15 minutes until lightly golden brown and set. Let cool completely before filling.

While the cookie crust is baking, combine the mascarpone (or softened cream cheese), sour cream, powdered low carb sweetener, and vanilla together into a bowl. Mix with a spatula until light and fluffy. Add to the cooled cookie crust and spread it evenly across the top.

Assemble the top with the fruit and place in the fridge to set. You can serve and slice this right away but I do like the filling to set back up slightly before slicing. Store in the fridge covered for up to a week.