Preheat the oven to 350°F. Line a baking sheet with parchment paper.
In a large mixing bowl, cream together the butter and sugar until light and fluffy.
½ cup unsalted butter, 1 cup granulated sugar
Add the egg and mix until well combined.
1 egg
Mix in the sour cream, and vanilla extract.
½ cup full-fat sour cream, 1 teaspoon pure vanilla extract
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
2 cups all-purpose flour, ½ teaspoon baking powder, ¼ teaspoon baking soda, ¼ teaspoon salt
Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
Drop the cookie dough by rounded tablespoons or a small cookie scoop onto the prepared baking sheet, leaving about 2 inches between each cookie.
Bake for 10-12 minutes or until the edges are lightly golden. Allow cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.
Allow them to cool for 30 minutes and then spread them with buttercream and garnish with sprinkles.
1 cup buttercream frosting, Gel food coloring for tinting buttercream, Sprinkles
Notes
Storage:
To Store: Store leftover cookies in an airtight container in the refrigerator for up to 3 days.
To Freeze: Bake and freeze your cookies for up to 3 months without the frosting. Completely thaw before adding the buttercream.
Tips:
Make sure your butter is softened to room temperature before beating.
Do not overmix the cookie dough or you will lose the beautiful light cakey cookie texture and have a tough cookie instead.
Do not overbake the cookies; they should just be slightly golden on the edges.
I like to line my baking sheets with parchment paper for easy clean up and cookie removal.
Make sure your cookies are completely cooled before frosting or the frosting may melt off.