Roll out cookie dough. Trace firefighter pattern with toothpick and cut out with craft knife. Cut dog with cutter. Bake and cool cookies. On dog, using tip 3, pipe in spots, features and fur (smooth with finger dipped in cornstarch), outline mouth and toes. Trace details on firefighter with toothpick; outline with tip 3. Pipe in mouth, tongue, emblem and inside helmet (smooth with finger dipped in cornstarch). Cover helmet, face, body, shoes and hands with tip 16 stars. Pipe tip 3 string eyes and ears; pipe dot nose and cheeks; print letters on emblem. Pipe tip 16 pull-out star hair. Outline and pipe in steering wheel with tip 3.
Ice cake sides and background areas smooth. Outline doors, windows and body of truck with tip 3. Pipe tip 3 dot gas cap, valves and headlight and string door handles (smooth with finger dipped in cornstarch). Using tip 12, outline ladder, pipe in fenders and hubcaps. Cover truck with tip 16 stars. Pipe tip 3 dot wheel centers. Add tip 21 swirl wheels. Pipe tip 21 shell bottom border. Print tip 3 message. With dots of icing, attach a marshmallow under each cookie for support. Position cookies on cake.
*Combine Lemon Yellow with Golden Yellow for yellow shown. Combine Red-Red with No-Taste Red for red shown.
The star tip creates the most celebrated, easily accomplished decorations! The serrated edges of the star tip make ridges in the icing as you squeeze it out. Because fill in requires so much piping from the same bag, keep replenishing icing in bag.