In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar together on medium speed until creamed, about 1 minute.
½ cup unsalted butter, ½ cup granulated sugar
Add the vanilla extract, egg, and salt. Mix to combine.
½ teaspoon pure vanilla extract, ½ teaspoon kosher salt, 1 large egg yolk
Slowly add the flour and mix just until the dough comes together in a ball.
1 cup all-purpose flour
Transfer the dough to the fridge to chill for 15 minutes. While the cookie dough chills, preheat your oven to 350°F.
Once the dough has chilled slightly, line two large baking sheets with parchment paper.
Scoop out a 2-tablespoon-sized piece of dough and gently roll it into a ball.
Flatten the ball of cookie dough slightly and use your thumb to create a well in the center of the dough.
Repeat with the remaining cookie dough, making sure to place the cookies at least two inches apart.
Bake for 12-14 minutes, or just until the edges are golden brown.
Remove the cookies from the oven and use a round cookie cutter to swirl them into circles--this will also help create a well to hold the caramel as they will slightly lose their shape while baking.
Set the cookies aside to cool while you prepare the caramel.