To start decorating the cookies, use a spatula or knife to cover the cookies or add frosting to a pastry bag with a small or medium tip and pipe onto cookies, then smooth out the frosting on top a bit.
To make the cute face, take some of the buttercream frosting and make a pink and a brown/black color. You'll need more pink than brown/black frosting.
For the brown/black frosting, place the frosting in pastry bag to pipe out eyes and nose with small round tip or if using a ziplock bag, snip a hole out of one of the corners to pipe out the eyes and nose, and mouth if you wish.
For the pink frosting, again, place the frosting in a pastry bag with a small round tip or or if using a ziplock bag, snip a hole out of one of the corners to pipe out the cute little cheeks and filled in the bunny ears.
I added some shimmery dusting powder, called rainbow on top, but you can leave as is, or add some shredded coconut or clear sanding sugar if desired. It's up to you how you want your bunnies to look!
Add any extras you wish, I added some rainbow ties out of rainbow candy and some of them I added mini m&m's for the eyes.
Allow cookies to set about 3 hours or overnight before stacking.