Step 1: Preheat the Oven. Begin by preheating your oven to 350°F (175°C) to ensure even baking.
Step 2: Cream the Butter and Sugar. In a large mixing bowl, combine the softened butter and sugar. Beat until light and fluffy, about 2-3 minutes.
Step 3: Add the Egg and Sour Cream. Mix in the egg and sour cream until well combined, scraping down the bowl as needed.
Step 4: Combine Dry Ingredients. In a separate bowl, whisk together flour, baking soda, baking powder, and salt. Gradually add to wet ingredients, stirring until just combined.
Step 5: Scoop and Bake. Drop rounded tablespoons of dough onto a lined baking sheet, bake for 10-12 minutes until edges are lightly golden.
Step 6: Cool the Cookies. Remove from oven, let cool on baking sheet for a few minutes, then transfer to a wire rack to cool completely.
Step 7: Make the Frosting. Combine powdered sugar, softened butter, vanilla extract, and milk until smooth. Add food coloring if desired.
Step 8: Frost and Decorate. Frost cooled cookies with a spatula and top with colorful sprinkles.
