Beat the 1 cup softened butter and 1/2 cup powdered sugar on medium speed for 3 minutes until pale and fluffy. Mix in the 1 tsp vanilla extract, then add the 2 1/4 cups flour and 1/2 tsp salt on low until the dough just comes together.

Scoop the dough into 12 portions of about 3 tbsp each, flatten to 1/2 inch thick, and bake on parchment-lined sheets at 325°F (160°C) for 13 to 15 minutes until the edges are just set. Cool on the pan for 5 minutes, then transfer to a wire rack.

Cook the 1 cup granulated sugar in a light-colored saucepan over medium heat, swirling once the edges melt, until deep amber and 350°F (175°C). Off the heat, stir in the 6 tbsp butter pieces, then slowly add the 1/2 cup warmed heavy cream. Stir in the 1/2 tsp flaky sea salt and let the caramel cool 20 to 25 minutes until spreadable.

Spoon about 1 tbsp caramel onto each fully cooled cookie and spread to a 1/4-inch-thick layer, leaving a small border around the edge.

Melt the 1 cup semi-sweet chocolate chips with the 1/2 cup heavy cream in a small saucepan over low heat for 3 to 4 minutes, stirring until smooth. Cool 5 minutes.

Drizzle the ganache across each cookie in a back-and-forth pattern, let it set for 15 minutes at room temperature, then arrange on a platter and finish with a pinch of flaky sea salt.