01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, and salt until well combined.
03 - In a large bowl, cream the butter and sugar until light and fluffy, approximately 2-3 minutes.
04 - Add eggs one at a time, beating well after each addition. Mix in vanilla extract and lemon zest until fully incorporated.
05 - Gradually add the dry ingredients to the wet mixture, alternating with the milk, mixing until a soft dough forms.
06 - Scoop tablespoon-sized pieces of dough and roll into 4-inch logs. Shape each log into a ring and pinch the ends to seal.
07 - Place rings on prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
08 - Bake for 12-15 minutes or until the bottoms are lightly golden. Transfer to a wire rack and let cool completely.
09 - Whisk powdered sugar, milk, and vanilla until smooth and slightly thick. Adjust consistency with additional milk if needed.
10 - Dip the top of each cooled cookie into the icing, then sprinkle with colored sprinkles. Allow icing to set before serving.