Line pan with plastic wrap. Prepare cereal treats recipe and press firmly into pan. Unmold onto foil-wrapped board.
Following label instructions, heat cookie icing; cover top of "cake" with cookie icing, letting icing drip down sides. Let set. With tubed icing, pipe rosette bottom border; position candy-coated chocolate on each rosette. On "cake" sides, pipe stars; position candy-coated chocolate on each star. Pipe rosette candleholders on top of "cake". Insert candles.