Things You'll Need
Grass decorating tip
Crusting buttercream frosting
Green food coloring gel
The grass frosting technique comes in handy for a variety of cakes and cupcakes, including sports-themed cakes and spring or Easter-themed cakes. Unlike green frosting spread to make a vague field of grass, this grass has individual blades and texture that more closely resembles the real thing. Use a special decorating tip to make grass with buttercream frosting. Or make grass from fondant, which might put you in mind of playing with playdough in your childhood. Fondant, a dough-like frosting, can be manipulated much the same as playdough.
Cut off the tip of a decorating bag and insert a grass tip, a multi-opening decorating tip with several small, round holes.
Tint crusting buttercream frosting green with food coloring gel, adding the gel a little at a time until you achieve the desired shade. Fill the bag with the green frosting. If desired, make two or three separate shades of green to achieve a more natural look like you would see on a real lawn. Squeeze the bag a few times to blend the different shades together without mixing them completely.
Spread a thin layer of green frosting over the cake where you want to make grass. While optional, this field of green provides a background so you can't see the cake through the frosting grass blades.
Hold the bag upright at a 90-degree angle to the cake or cupcake surface, positioning the tip about 1/8 inch above the surface.
Squeeze the bag with firm pressure to push the frosting through the holes in the grass tip. Stop squeezing the bag when the grass reaches the desired height. Pull the tip straight away from the cake or cupcake. If you want grass longer than 1/8 inch, lift the bag away from the cake slowly. Grass looks best when it's no more than about 1/2 inch long.
Reposition the tip directly beside the first bit of piped grass. Squeeze the bag to make a second tuft of grass, stopping and pulling away when you reach the desired height. Repeat this process until the desired area is filled in with grass. Occasionally, pull the tip away to the left or right instead of straight up to help make the frosting grass appear more like real grass.
Apply green food coloring gel to a small ball of rolled fondant. Knead the fondant in your hands to incorporate the color, adding more gel as needed to achieve the desired shade. You can make different shades of green and knead them a few times to blend the colors without mixing them completely.
Cover the cake with green fondant in the same shade as the fondant grass. This is optional but makes it so you can't see the background through the grass. You can cover the entire cake with green fondant or only the part of the cake where you wish to make grass.
Place the green fondant in a garlic press, using just enough at a time to fill the chamber without over-stuffing it. Garlic smell and flavor is difficult to remove completely even with thorough washing, so it's best to purchase a second press for use only with cake decorating.
Hold the garlic press just above the cake. Squeeze the garlic press handle to push the fondant out through the garlic press holes and onto the cake. Stop squeezing when you achieve the desired length. Pass the blade of a sharp knife across the garlic press head to cut the fondant. Reposition the garlic press beside the first tuft of grass and squeeze to make a second tuft.
Separate any blades of fondant grass that stick together with a toothpick. You can also use the toothpick to push some of the grass to the side to mimic the look of natural grass.
You can make buttercream frosting grass even without a grass decorating tip. Use a small round tip or simply cut a small hole in the tip of a decorating bag. The action is the same as with a grass tip, but it makes a single blade of grass at a time.
Crusting buttercream frosting is made with vegetable shortening in place of at least half the butter in a buttercream recipe. It holds its shape at room temperature better than butter and becomes stiff when dry so the grass holds its shape better.
Try a wire mesh sieve as an alternative to the garlic press for fondant grass. Press on the fondant with your thumbs to push it through the sieve holes. This creates a larger mound of grass that you can cut off with a knife and set on the cake.
Try this same technique with other colors of frosting to make monster or animal fur.