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 until evenly combined.
03 - Beat softened butter and granulated sugar with electric mixer until light and fluffy, approximately 3 minutes.
04 - Mix in egg and vanilla extract until fully incorporated into butter mixture.
05 - Gradually blend dry ingredients into wet mixture, mixing just until dough forms. Avoid overmixing.
06 - Divide dough into two discs, wrap in plastic, and refrigerate for minimum 30 minutes.
07 - Roll dough on floured surface to 1/4-inch thickness. Cut with bunny-shaped cutter and place 2 inches apart on baking sheets.
08 - Bake 8 to 10 minutes until edges barely turn golden. Cool completely on wire rack.
09 - Beat softened butter until creamy. Gradually incorporate powdered sugar, milk, and vanilla. Mix until smooth and spreadable. Tint with food coloring if desired.
10 - Frost cooled cookies using piping bags or spatulas. Add candy eyes or sprinkles for bunny faces. Allow frosting to set before serving.