Preheat the oven to 350°F. Line two baking sheets with parchment paper and set aside.
In a bowl of a stand mixer fitted with the paddle attachment or using an electric hand mixer, cream together the butter and granulated sugar until light and creamy (about 2-3 minutes).
Scrape the bottom and sides of the bowl. Add the cold egg, mix on medium speed for 20 seconds, then add the egg yolk. Scrape down the sides, add vanilla extract, and Salted Caramel Artisan Flavor Paste. Mix on low until combined.
Sift in the flour, Dutch-processed cocoa powder, baking soda, and salt. Mix just until the dry mixture disappears.
Use a 3-tablespoon cookie scoop to form 12 equally sized cookie dough balls. Place them on the prepared baking sheets and gently flatten to about a little over ½ inch in thickness.
Bake in the preheated oven for 8-9 minutes. Let the cookies cool on the baking sheets for 10 minutes before transferring them to a cooling rack.
For the Frosting:
In a large mixing bowl, cream together the room temperature butter and cream cheese on medium speed until smooth and well combined.
Add the powdered sugar and heavy cream to the butter and cream cheese mixture. Mix on low until combined, then cream on medium-high speed for 3 minutes.
Add the Natural Salted Caramel Artisan Flavor Paste to the mixture. Mix on medium speed until evenly combined (about 1 minute).
Assembly:
Once the cookies are completely cooled, spread or pipe the Salted Caramel Buttercream frosting onto the cookies.
I used my salted caramel sauce to create that swirl on top! You can find that recipe here (scroll down to the bottom)