Prep the Oven and Pan
Preheat your oven to 325°F. Lightly coat a 9×13-inch baking dish with nonstick spray or line with parchment paper.

Make the Dough
Using a stand mixer with the paddle attachment, beat the butter, granulated sugar, and powdered sugar on medium speed for 2 minutes until fluffy. Add vanilla and mix well. Lower the speed and slowly add in the flour until a soft dough forms.

Form the Crust
Press one-third of the dough evenly into the bottom of the prepared baking dish. Wrap the remaining dough in plastic wrap and place it in the refrigerator to chill.

Bake the Bottom Layer
Bake the crust for 20 minutes, or until the edges are lightly golden. Remove from the oven and place on a wire rack to cool for about 15 minutes.

Make the Caramel Filling
While the crust cools and the remaining dough chills, place the unwrapped caramels and milk or cream in a microwave-safe bowl. Microwave on high for 1 minute, stir, then continue heating in 30-second intervals, stirring each time until completely smooth. Stir in vanilla.

Assemble the Bars
Pour the caramel over the cooled crust. If using sea salt, sprinkle it evenly over the caramel layer.

Add the Topping and Bake
Take the remaining chilled dough and crumble it over the caramel layer. Return the pan to the oven and bake for another 25 to 30 minutes, until the top is golden and the caramel is bubbling.

Cool and Slice
Let the bars cool thoroughly to ensure clean, neat cuts when slicing into squares.