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