Instructions

1. Preheat the oven to 350°F and line a baking sheet with parchment paper. Set aside.
2. In a standmixer fit with the whisk attachment, beat the room temperature butter and granulated sugar until light and fluffy, about 1 minute. Scrape down the bowl and add the egg, sour cream and vanilla and beat until combined.
3. Scrape down the bowl and add the flour, baking powder, baking soda, and salt. Beat until no streaks or clumps of flour remain, but do not over mix.
4. Use a 1.5 ounce cookie scoop to scoop out the dough into balls and place 2 inches apart onto your cookie sheet.
5. Bake at 350°F for 13 minutes or until the edges are set, but the cookies are still a bit underdone in the middle. Place on a wire rack to cool completely.
6. While the cookies cool, make the frosting. In a small mixing bowl, combine the powdered sugar, 3 tablespoons of milk, corn syrup, vanilla extract and salt. Whisk together until smooth. If the frosting is too stiff, add the additional tablespoon of milk to reach the desired consistency.
7. Transfer half of the frosting to a separate mixing bowl to make the chocolate frosting. Add the cocoa powder to this half of the frosting and mix until smooth and creamy. Now you should have one bowl of vanilla frosting and one of chocolate!
8. Flip the cooled cookies over so that the flat bottom is up. Use an offset spatula to frost one half of a cookie with a thin layer of vanilla frosting. Repeat with all the cookies and place the cookies in the fridge for 10 minutes to let the frosting set. Remove the cookies from the fridge and frost the other half of each cookie with the chocolate frosting. Place back in the fridge for the frosting to set until ready to serve!