Make the Cookie Dough: Melt the butter in a large mixing bowl and allow to cool for a few minutes so it's not hot. Whisk in the room temperature sour cream until smooth. Whisk in the sugars, then the eggs and vanilla. Add the dry ingredients and fold in with a spatula (or use a mixer) until completely combined. Scrape the sides and bottom of the bowl to make sure all dry bits are incorporated.
10 tbsp salted butter, melted and cooled slightly, 1/2 cup full fat sour cream, at room temperature , 3/4 cup granulated sugar , 3/4 cup light brown sugar, packed, 2 large eggs, at room temperature , 2 tsp vanilla extract , 3 and 1/4 cups all-purpose flour, spooned & leveled or weighed out, 1 tsp baking soda, 1 tsp baking powder, 1/2 tsp salt, 1 tsp cinnamon
Chill & Roll Balls: Cover the bowl with plastic wrap or a clean kitchen towel and pop in the freezer for a quick initial chill for 20-30 minutes, so the dough is easier to handle & roll. Roll dough into balls that are 60 grams in size. Continue chilling dough balls on a lined baking sheet covered with plastic wrap for at least 2 hours in the fridge or 45 minutes in the freezer. 1/3 cup granulated sugar
Bake Cookies: Preheat your oven to 365℉. Line a few cookie sheets with parchment paper. Roll chilled cookie dough balls in granulated sugar, and place 5-6 cookies on each sheet. (Keep extra cookies in the fridge while they wait their turn to bake.)Bake each pan of cookies for 11-13 minutes. The cookies will be puffy and crinkly and the edges should look and appear set. Let cookies cool on the baking sheet on a wire rack for 5-10 minutes, then transfer to a cooling rack to finish cooling completely. Brown Butter for the Frosting: In a nonstick pan over medium heat, melt the butter. Continue cooking the butter – stirring constantly. The butter will get foamy, then bubbly, then start to turn turn golden brown and develop a nutty/caramely aroma. Once it reaches a deep golden color, remove from the heat and pour into a bowl to chill in the fridge or freezer until it's room temperature. It doesn't have to come back to solid before using in the frosting, but it can't be warm.
3/4 cup salted butter, cubed, 8 ounces full fat cream cheese, 4 cups powdered sugar , 1 tbsp vanilla extract , pinch of salt
Make the Frosting: Beat together melted & cooled brown butter with cream cheese in a large bowl with an electric mixer for 1 minute or so, until creamy. It will look odd at first but will smooth out. Add half the powdered sugar and mix until incorporated. Add the remaining powdered sugar, vanilla, and a pinch of salt and mix until creamy.
Frost Cookies: Divide the frosting into three bowls, and color one portion green, one red, and leave one white. To make the shade green I have, use leaf green and bit of golden yellow gel food coloring. To make this shade of red, use deep red gel food coloring with a bit of burgundy and a hint of black. Use a small cookie scoop to plop dollops of frosting onto each cookie, then spread it with an offset spatula. Top with white sanding sugar if desired, for a little sparkle. gel food colorings
Serve & Store: Store frosted cookies in an airtight container in the fridge for 5-7 days. Unfrosted cookies can be stored in a container at room temperature for 1-2 days before frosting them.
Make-Ahead Tips: Cookie Dough: Cookie dough balls can be chilled in an airtight container in the fridge for up to 3 days before baking. Cookie dough balls can be frozen on a lined baking sheet, then transferred to an airtight container or freezer bag once solid. Freeze for 1-2 months, baking from frozen and adding 1-2 minutes as needed. Frosting: Frosting can be made 1-2 days ahead, covered, and refrigerated. Let come back to room temperature for 20-30 minutes and beat with electric mixer to get it back to a spreadable consistency before using.