In a large mixing bowl, combine the all-purpose flour, granulated sugar, and salt. Add the cold, unsalted butter cut into small cubes. Using a pastry cutter or your fingers, mix until the mixture resembles coarse crumbs.

Form the Dough

Gradually add ice water, one tablespoon at a time, mixing until the dough just comes together. Do not overmix. Shape the dough into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour.

For the Apple Filling

Prepare the Apples

Core, peel, and slice the Granny Smith apples. Place them in a large bowl.

Mix the Filling

In a separate bowl, combine the brown sugar, ground cinnamon, lemon juice, cornstarch, and vanilla extract. Pour this mixture over the sliced apples and toss to coat evenly.

Assembly and Baking

Preheat the Oven

Preheat your oven to 375°F (190°C).

Roll Out the Dough

On a floured surface, roll out the chilled tart dough into a circle about 12 inches in diameter. Carefully transfer it to a 9-inch tart pan, pressing it into the edges.

Fill the Tart

Pour the apple filling into the tart shell, spreading it evenly.

Bake the Tart

Bake in the preheated oven for 45-50 minutes, or until the apples are tender and the crust is golden brown.

Cool the Tart

Remove the tart from the oven and let it cool for at least 30 minutes before serving.

For Serving

Serve the Tart

Slice the rustic apple tart into wedges and serve warm with scoops of vanilla ice cream. Drizzle with caramel sauce to taste.