Sour Cream Cookies

Whisk the flour, baking powder, baking soda, and salt together. Set aside.

In a large bowl using a hand mixer or stand mixer fitted with a paddle attachment, beat the butter and granulated sugar together on high speed until light and creamy, about 3-4 minutes. Scrape down the sides and up the bottom of the bowl with a spatula as needed.

Add the eggs, one at a time, stirring on a low speed until fully blended in. Then add the vanilla and sour cream, and blend on medium-high speed until combined. Scrape down the sides and up the bottom of the bowl as needed. If the mixture looks a little curdled, don't sweat it, things will smooth out when you add the dry ingredients .

With the mixer on low speed, mix in the dry ingredients until combined. The dough will smooth and creamy with a texture somewhere between a cookie dough and cake batter.  Cover the bowl tightly plastic wrap and chill the dough for at least 1 hour, up to 2-3 days.

Preheat the oven to 350°F and line baking sheets with parchment paper or silicone baking mats.

Remove cookie dough from the refrigerator. Using a 1.5 tablespoon sized scoop, form large cookie dough balls each, spaced at least 3" apart on the baking sheets.

Bake for 12-14 minutes, rotating the pans halfway through for an even bake. Remove from the oven and allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before frosting.

Chocolate Sour Cream Frosting

In a medium microwave safe bowl, melt the chocolate in 15-second increments, stirring often, until smooth and melted.

In a medium bowl when using a hand mixer or in the bowl of a stand mixer fitted with a paddle attachment, beat together the chocolate and the butter until smooth.

Blend in the powdered sugar. Then beat in the sour cream and the vanilla. The frosting should be thick and creamy. *If the looks a little runny, refrigerate for 15-20 minutes, it's firmed up enough to spread. Then blend until smooth before spreading on cookies.

Use immediately for best results, or store covered in the refrigerator.

Assembling the Cookies

Use a small spatula or offset spatula to generously frost each cookie with swoopy swirls of the frosting. Then optionally top with sprinkles for a festive finish.