In advance: Make candy trims. Tint portions of melted white candy pink, yellow, green and orange using candy colors. Mold 2-tone letters in Alphabet Mold Set using layering method; fill cavities 1/4 deep with melted pink candy, chill until firm and fill remainder of mold with melted cocoa candy. Chill until firm. Mold 4 swirls in each color using Dessert Accents Mold. Chill until firm; unmold.

Bake and cool 2-layer 8 in. square. Ice cake smooth. Attach candy swirls and confetti sprinkles to cake sides with tip 2 dots of icing. Pipe tip 6 bead top and tip 10 bead bottom borders. Position letters. Pipe tip 10 dots for candle holders; insert candles.