The marshmallows on Bunny Hill seem to multiply like rabbits. The parents are regular size, and their juniors are miniature. Stashed away inside their hill is a sweet mound of candy carrots.
Spoon the dark chocolate frosting into a Ziplock bag. Spoon 2 tablespoons of the vanilla frosting into a Ziplock bag. Press out the excess air and seal the bags. Tint the remaining vanilla frosting light green with the green and yellow food coloring. Cover with plastic wrap to prevent drying.2.
Line a cookie sheet with wax paper. As you make the parts, transfer them to the cookie sheet. Place the pink sugar in a small bowl. For the large bunny ears, use sharp craft scissors to cut 1 of the large marshmallows crosswise into 4 thin slices, allowing the 4 pieces to fall into the pink sugar. Shake the bowl and press the cut sides of the marshmallow pieces into the sugar to coat. Remove the pieces from the sugar bowl and brush any excess sugar off the sides. Repeat with 25 of the mini marshmallows to make 100 small bunny ears. For the large bunny legs, cut a ½-inch piece from each flat end of 1 large marshmallow, discarding the center. Cut each piece in half crosswise, to make 4 semicircles. For the small bunny legs, cut 50 mini marshmallows in half crosswise.3.
Place the white candy melts in a Ziplock bag; do not seal the bag. Microwave for 10 seconds to soften, massage the candy in the bag, return to the microwave, and repeat the process until smooth, about 30 seconds. Press out the excess air and seal the bag. Snip a small (1/8-inch) corner from the bag.4.
To assemble the bunnies, pipe a dot of melted candy on the flat side of a whole marshmallow for the body. For the head, press another whole same-size marshmallow into the candy on its side. Lay the partially assembled bunny on its back, pipe a dot of melted candy on each side of the body near the bottom, and attach the leg pieces cut from the same-size marshmallow. Pipe a dot of melted candy on the top of the head and arrange 2 sugared marshmallow ears made from size-size marshmallow, sugar side facing forward (see photo). Repeat to make 2 large and 50 baby bunnies. Refrigerate until the melted candy is set, about 5 minutes.5.
Snip a very small (1/16-inch) corner from the bags with the dark chocolate and vanilla frostings. For the nose, attach a heart decor to the front flat side of each marshmallow head with a dot of vanilla frosting. Pipe the eyes with the dark chocolate frosting.6
Line a cookie sheet with wax paper. Arrange the carrot-shaped candy in rows on the cookie sheet. Place the green candy melts in a Ziplock bag; do not seal the bag. Microwave for 10 seconds to soften, massage the candy in the bag, return to the microwave, and repeat the process until smooth. Press out the excess air and seal the bag. Snip a small (1/8-inch) corner from the bag. Pipe a ½-inch-long wavy line onto one end of each candy as the leafy top (see photo). Refrigerate until the melted candy is set, about 5 minutes.7.
Place the chilled cake, flat side up, on a work surface. Trim the top of the cake level; reserve the cake trimmings for the dirt. Using a small knife, cut a 3-inch circle, about 2½ inches deep, from the center of the cake. Reserve the removed cake for the dirt.8.
Gently remove the carrots from the wax paper. Fill the opening in the cake with the carrots. Cut a cardboard circle to fit on top of the cake, place it on the cake, and invert the cake, rounded side up. Place the cake on a serving platter. Spread the light green frosting on the cake and make soft swirls with an offset spatula or the back of a spoon. Stand the marshmallow bunnies all over the cake, pressing into the frosting to secure. Add patches of green sprinkles for grass. Crumble the reserved cake pieces and sprinkle around the cake as dirt.