01 - Whisk together flour, baking powder, and salt in a medium bowl. Set aside for later use.
02 - Beat the butter and sugar together in a large bowl until light and fluffy, approximately 2–3 minutes.
03 - Add the egg, vanilla extract, and almond extract if using. Beat until thoroughly combined.
04 - Gradually add the dry ingredients to the wet mixture, mixing just until a dough forms. Avoid overmixing.
05 - Divide dough in half, flatten into discs, wrap in plastic wrap, and refrigerate for at least 1 hour.
06 - Preheat oven to 350°F. Line baking sheets with parchment paper.
07 - On a lightly floured surface, roll out one dough disc to 1/4-inch thickness. Cut out bunny shapes with a cookie cutter.
08 - Place cookies 2 inches apart on prepared baking sheets.
09 - Bake for 9–11 minutes, until edges are just lightly golden. Cool on sheets for 5 minutes, then transfer to a wire rack to cool completely.
10 - Beat together powdered sugar and egg whites (or meringue powder + water) on low speed until combined, then increase speed and beat until stiff peaks form, about 5 minutes. Add additional water for flooding consistency if needed.
11 - Divide icing into bowls and tint with gel food coloring as desired.
12 - Decorate cooled cookies with royal icing using piping bags or squeeze bottles. Add sprinkles or pearls before icing sets.
13 - Allow icing to fully set for 2–4 hours before storing or serving.