In a large mixing bowl, cream together 1 cup of softened butter and 1 cup of granulated sugar until light and fluffy. Add the egg and 1 teaspoon of vanilla extract, mixing until smooth.

In a separate bowl, whisk together 2 1/2 cups of all-purpose flour, 1/2 teaspoon of baking powder, and 1/4 teaspoon of salt. Gradually add this dry mixture into the wet ingredients until well combined.

Wrap the dough in plastic wrap and chill it in the refrigerator for about 1 hour.

While the dough is chilling, preheat your oven to 350°F (175°C).

On a lightly floured surface, roll out the chilled dough to a 1/4-inch thickness. Use a bunny-shaped cookie cutter to cut out shapes and place them on parchment-lined baking sheets.

Bake in the preheated oven for 8–10 minutes or until the edges are lightly golden. Let them cool completely on a wire rack.

In a mixing bowl, beat 1/2 cup of softened butter until smooth. Gradually add 2 cups of powdered sugar, 1/2 teaspoon of vanilla extract, and 1–2 tablespoons of milk. Beat until fluffy.

Divide the frosting into bowls and tint each with pastel gel food coloring.

Once the cookies are cool, frost each cookie and sprinkle colored sanding sugar and add chocolate chips or black gel for eyes.

Let the frosting set before serving or packaging.