In a large bowl, whisk together the cake flour, baking soda, cream of tartar, baking powder, and salt, set aside.
In the body of a stand mixer with the paddle attachment, cream the butter until smooth.
Mix in the powdered sugar until combined, scrape down the sides if needed.
Add the sour cream, egg, vanilla extract, and almond extract, stir it in until fully combined, mixture may appear curdled.
Add the flour mixture and stir in until combined, scrape down the sides, and put the mixer on medium speed for a few seconds to make sure it’s mixed well.
On a parchment-lined baking sheet, make dollops of dough, not touching with a 1.5 tablespoon cookie scoop. Cover with plastic wrap and place in the fridge for at least 2 hours or overnight preferably.
Preheat the oven to 375°F. Line 2-4 sheet trays with parchment paper. Roll the dough balls in your hands so they are round. Using the heel of your hand, gently flatten the balls of cookie dough. Bake for 8-10 minutes until the edges begin to turn slightly light golden brown. Let cool completely on the baking sheet.
While the cookies are baking, make the frosting by adding the butter to a large bowl and with a hand mixer (or with a stand mixer) whip the butter until smooth.
Add the powdered sugar and salt combine as well as you can.
Add the milk and vanilla, slowly stir it in. Turn the mixer on medium speed and whip it for 3 minutes until light and fluffy, scrape down the sides as needed. If it seems too thick add another ½ tablespoon of milk.
Add food coloring now if using. Scrape down the sides to make sure all the frosting is colored.
Once the cookies are cooled, add a little bit of the frosting to each one and immediately top with sprinkles. Repeat with all the cookies.