Slice off both ends of the watermelon with a sharp knife to create flat surfaces for stability.
Cut the watermelon into thick, even slices approximately 1 to 1.5 inches thick, creating multiple 'layers' for the cake structure.
Arrange the watermelon slices on a large serving platter, stacking alternate slices slightly offset to resemble a tiered cake, maintaining their natural shape and vibrant color.
Optional: Decorate the top of the watermelon cake with small fruit slices, mint leaves, or additional garnishes for visual appeal.
Serve immediately or refrigerate briefly before slicing and presenting to maintain freshness and juiciness.