Measure out all ingredients and sift together the flour, baking powder, and salt in a medium bowl, whisking gently to combine and aerate. Set the dry mixture aside. Remove eggs from the refrigerator to bring to room temperature (about 70°F) while you prepare the butter and sugar—this helps them incorporate smoothly into the dough and creates a better texture in the final cookies.

In a large mixing bowl, combine the softened butter and sugar, beating on medium speed for 3-4 minutes until the mixture is pale, fluffy, and nearly doubled in volume. This creaming process incorporates air and creates a lighter, more tender cookie. I like to use Kerrygold unsalted butter because it has a richer flavor that really comes through in the final cookie.

Add room temperature eggs one at a time to the creamed butter and sugar, beating well after each addition. Pour in the vanilla extract and mix until fully combined. The mixture should look smooth and slightly lighter. If it looks separated or curdled, don't worry—it will come together when you add the dry ingredients.

Add the dry ingredient mixture from Step 1 to the wet mixture from Step 3, stirring on low speed until just combined—don't overmix, as this keeps the cookies tender. Divide the dough in half, wrap each portion tightly in plastic wrap, and refrigerate for at least 6 hours or overnight. This chilling time allows the dough to rest and makes it much easier to roll out and cut without sticking.

Preheat your oven to 325°F. Remove one portion of dough from the refrigerator and let it soften slightly for 10-15 minutes at room temperature for easier rolling. On a lightly floured surface, roll the dough to about 1/4-inch thickness and cut out bunny shapes using a bunny-shaped cookie cutter. Place cut-outs on parchment-lined baking sheets, spacing them about 1 inch apart. Bake at 325°F for 8-10 minutes until the edges are just set but the centers are still slightly soft—the cookies will continue to cook slightly as they cool. Let them cool on the baking sheet for 10 minutes, then transfer to a wire rack.

In a clean, grease-free bowl, combine egg whites, powdered sugar (sifted to remove lumps), and cream of tartar. Beat on medium speed for about 4 minutes until stiff peaks form—the icing should be glossy, smooth, and hold its shape when piped. Divide the icing into separate bowls, add your desired gel food coloring to each bowl, and stir well. I prefer AmeriColor gel coloring because it gives vibrant, consistent bunny ear colors without thinning the icing like liquid food coloring would.

Using a piping bag fitted with a small tip, pipe the colored icing onto the cooled cookies from Step 5, focusing on the bunny ears and face. Let the icing set for 2-3 hours at room temperature. Once the base colors have set, use black icing (or a black gel coloring in a fresh batch of white icing) to carefully pipe small eyes and a nose on each bunny. Allow another 2-3 hours for all icing to fully cure and harden before serving or storing.