• Preheat oven to 350F (175C) and line a baking sheet with parchment paper or silicone baking mat. Set aside.

Batter

• Whisk together 2 ½ cups All-purpose flour, 1 teaspoon Baking powder, ½ teaspoon Baking soda, and ½ teaspoon Salt in a medium bowl.
• Use a stand mixer or electric mixer to blend ½ cup Unsalted butter and 1 cup Granulated sugar until light and fluffy.
• Add ½ cup Sour cream, 1 Large egg, and 1 teaspoon Vanilla extract. Add 1 teaspoon Fresh lemon zest (if desired) and beat together until the mixture is creamy.
• Gradually add dry ingredients to wet, combining thoroughly without overmixing.

Baking

• Scoop dough with a cookie scoop or 1 ½ Tablespoon sized scoop and drop onto prepared baking sheet. Space approximately 2 inches apart. Transfer to the center rack of preheated oven and bake until the edges begin to turn golden, and the tops are well domed, about 10-11 minutes
• If you desire flatter tops for icing (pictured), lightly press the tops with the bottom of a flat glass, clear bowl, or measuring cup immediately after the cookies come out of the oven. Cool completely before decorating.

Glaze and Decorate

• Add 2 Tablespoons Sour cream,1 teaspoon Vanilla extract, and 1-2 Tablespoons Milk and beat together to combine in a medium mixing bowl. Sift 1 ½ cups Confectioner's sugar if clumps are visible. Gradually add powdered sugar and whisk until completely smooth, adding more milk if necessary. Add a few drops of Food Coloring to evenly tint the glaze.
• Once cookies are completely cooled, pour or dip the tops in the icing. Add Sprinkles and any other decorations before the glaze dries.