In a stand mixer or with a hand mixer, cream the butter until it is completely smooth. Add the sour cream and sugar, and mix until there are no clumps. Beat in the egg, vanilla, and almond extract
In a separate bowl, mix the cake flour, baking soda, baking powder, cream of tartar, and salt
Slowly add a little of the dry mixture to the wet at a time and mix, ensuring it is fully encorporated. The dough should be thick and sticky. Place the mixing bowl of dough in the fridge for 10-15 minutes
Preheat the oven to 400° F and prepare a baking sheet with parchment paper or silicone baking mats
Scoop out the cookie dough in about 1 tbsp balls. Roll them gently between your hands to create smooth round balls. Once they are lined up on a baking sheet, gently press the tops of them flat with the bottom of a glass cup
Bake for 9 minutes. They should be soft to the touch but after 5-10 minutes will set to the appropriate texture. Cool cookies completely before frosting them