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 well combined.
03 - Beat softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 3 minutes.
04 - Mix in the egg and vanilla extract until fully incorporated into the butter mixture.
05 - Gradually add the dry ingredients to the wet mixture, mixing just until the dough forms a cohesive ball.
06 - Divide dough into two discs, wrap separately in plastic wrap, and refrigerate for at least 30 minutes.
07 - On a lightly floured surface, roll dough to 1/4-inch thickness. Cut with a bunny-shaped cookie cutter and place 2 inches apart on prepared baking sheets.
08 - Bake for 8 to 10 minutes until edges are lightly golden. Cool completely on wire racks.
09 - Beat softened butter until creamy. Gradually add powdered sugar, milk, and vanilla extract, continuing to beat until smooth and spreadable. Tint portions with food coloring if desired.
10 - Frost cooled cookies with buttercream using piping bags or spatulas. Add candy eyes or sprinkles to create bunny faces. Allow frosting to set before serving.