Line two baking sheets with silicone baking mats or parchment paper. Set aside.

Place the butter, brown sugar, vanilla extract, and cinnamon into a large mixing bowl. Use a hand mixer to beat on medium speed until mixture is pale and well combined, about 1 minute.

Add the flour and salt to the bowl and beat on low speed, scraping the sides of bowl with rubber spatula as needed, until a smooth dough forms.

Divide cookie dough into 24 balls, using about 2 tablespoons for each, and arrange on the baking sheets at least 1 inch apart. Transfer the sheets to the freezer for 10-15 minutes while oven preheats. Alternately, place the dough balls on a small baking sheet or large plate to freeze, and transfer to the baking sheets for baking.

Preheat the oven to 350°F.

Remove cookies from the freezer. Bake cookies on middle rack of oven until puffy and golden brown at edges, 14-16 minutes.

Check to see that cookies are done. Remove from oven or add time as needed.

Immediately press a 1/4-inch-deep indent into the center of each cookie, using either the handle of wooden spoon or your thumb. Making deeper indents will help avoid creating cracks in the cookies.

Allow the cookies to rest and firm up on the sheets for 5-10 minutes, then transfer to a wire rack. Spoon about 3/4 teaspoon of salted caramel sauce into the indent of each cookie. Allow to cool and set completely before serving. Store leftover cookies in refrigerator.