Preheat oven to 350 degrees and line a baking sheet with parchment paper.
In the bowl of a stand mixer or a large bowl with an electric hand mixer, cream together the soft butter and granulated sugar for 90 seconds until fluffy.
Add in eggs, sour cream, and vanilla extract. Beat on medium-high speed until. Well combined. The mixture will not be smooth and that is ok. Scrape down the sides and bottom of the bowl as needed.
Make a well in the middle of the batter and add flour, baking powder, baking soda, and salt. Start with the mixer at a low speed and slowly increase speed as the dry ingredients become incorporated. This will be a very thick and creamy batter, not a traditional dough.
Using a cookie scoop (1.5Tbsp) drop dough 2 inches apart on the cookie sheet. I bake 12 cookies per pan.
Bake cookies for 12-13 minutes until set. The edges won’t be brown but they will look set and not shiny on top. They will be slightly golden brown on the bottom.
Let cookies cool on the cookie sheet for a few minutes before removing them to a wire cooling rack. Let cool completely before frosting.
To make the frosting, use an electric mixer to beat butter for a full 2 minutes. It will be fluffy and start to get creamy.
Slowly add in 2 cups of powdered sugar, heavy cream, and vanilla extract. Beat until creamy while adding the last 2 cups of powdered sugar.
Beat for another full 2 minutes until the frosting is fluffy and creamy and nearly white. You shouldn’t see any streaks of butter. Lastly, add in a few drops of gel food coloring. Mix until it is your desired color. Frost the cooled cookies and top with sprinkles. Enjoy!