In a medium bowl whisk together the flour, baking soda, baking powder and salt; set aside.
In the bowl of a stand mixer with the flat beater attached, cream the butter and granulated sugar at medium speed until light and fluffy, about 3 minutes. Scrape down the sides of the bowl with a rubber spatula as needed. Add the eggs, one at a time, beating until each is incorporated. Add the vanilla and sour cream and beat at low speed until combined.
Add the dry ingredients and beat at low speed until just combined, scraping down the bowl as needed. Dough will be a bit “sticky”. Divide dough into two sections. Flatten into rectangles about 1½ inches thick, then wrap with plastic wrap. Chill in the refrigerator overnight or at least two hours until firm.
Preheat the oven to 425 degrees F. Line large baking sheets with parchment paper; set aside.
Flour the countertop and the top of the dough. With a rolling pin, roll the dough out to ¼-inch thickness. Using a 2 1/2-inch round cookie cutter, cut out circles and transfer to a baking sheet. Bake for 7 minutes, until pale golden. Immediately transfer cookies to a wire rack to cool. Cook cookies completely before frosting.
Make the Frosting: In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and vanilla. Slowly beat in the powdered sugar and the pinch of salt. Once smooth and creamy, add in heavy cream, 1 tablespoon at a time, then beat at medium-high speed for a minute or two until light and fluffy. If desired, add food coloring and beat until combined.
Once cookies have cooled completely, frost and add sprinkles. Allow frosting to set, then store in an air-tight container. Let cookies sit for several hours before serving to allow the flavors to develop.