Preheat the oven to 350° F.

In a medium bowl, combine the flour, sugar, cornstarch, and salt. Add melted butter, olive oil, and milk. Stir until all the ingredients are well-combined and a crumbly dough forms.

Press the dough into your tart shell, starting from the sides and then moving to the center. The sides should be a bit thicker than the bottom.

Prick the bottom of the tart shell with a fork and place in the oven to bake until golden-brown and crisp, 20-25 minutes.

Remove it from the oven and allow to cool for a few minutes.

In the meantime, add the chocolate and heavy cream to a medium saucepan and place over low heat. Allow the chocolate to melt while stirring frequently to prevent burning. Once the chocolate is melted, remove from heat and stir in the Kahlua and vanilla extract.

Pour the chocolate Kahlua filling over the baked tart shell and place the tart in the refrigerator to set for a couple hours.

Sprinkle with flakey sea salt or any other desired toppings.

Enjoy!