Melt various colors of Candy Melts following package instructions.
Drizzle 2 or more colors melted candy in open design into Dessert Dome candy mold. Chill until set, about 5 minutes. Fill candy mold, following package instructions with additional melted candy, marbled if desired; chill until firm, about 15 minutes. Unmold.
Place largest square Cut-Out and round cookie cutter on cookie pan; fill 1/4 in. full with melted candy; immediately spoon in 2nd and 3rd, if desired, color and marble. Refrigerate until firm, about 10 minutes. Remove from Cut-Out or cutter mold. Attach shell to base with melted candy; let set.
Fill dessert shell with mousse, ice cream, pudding, berries, cut-up fruit or anything desired. Top with sprinkles, icing decorations or sugars.