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, beat softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 3 minutes.
04 - Beat in the egg and vanilla extract until fully incorporated into the mixture.
05 - Gradually add dry ingredients to the wet mixture, mixing just until dough forms. Be careful not to overmix.
06 - Divide dough into two equal discs, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes.
07 - On a lightly floured surface, roll out dough to 1/4-inch thickness. Use a bunny-shaped cookie cutter to cut out cookies and place them 2 inches apart on prepared baking sheets.
08 - Bake for 8 to 10 minutes, or until edges just begin to turn golden brown. Transfer to a wire rack and let cool completely.
09 - Beat softened butter until creamy. Gradually add powdered sugar, milk, and vanilla extract, beating until smooth and spreadable. Tint portions with food coloring as 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.