For best results, use a stabilized whipped cream that does not melt at room temperature (commercial whipped cream from a can will not work; frozen from a tub might). If serving a crowd, use just two slices of melon with lots of whipped cream, mixing up the top and bottom melon colors so everyone gets something different.
1each melons in different colorstry red watermelon, cantalope, honeydew, and yellow watermelon
1teaspoonunflavored gelatin
4teaspoonscold water
1cupcoldheavy whipping cream
1/4cupconfectioner's sugar
Instructions
Before beginning, place your whipping bowl and whisk blades in the freezer so they're very cold when starting the whipped cream.
Slice the melons into equally sized shapes (squares, rectangles, or circles). Keep them under 4" wide, so the stacks will be stable. Place the melon slices in the refrigerator while you make the whipped cream.
In a small pan, combine gelatin and cold water; let stand until softened, about 5 minutes.
Place over low heat, stirring constantly, just until the gelatin dissolves. Remove from heat and cool, but don't allow it to set - it should still be a liquid.
Whip the cream with the confectioner's sugar, until it begins to thicken, with the beaters leaving tracks in the cream.
Add the gelatin to the whipping cream in a steady stream and whip at high speed until stiff peaks form.
Remove the melons from the fridge and thoroughly pat all sides dry with paper towels. (They have be as dry as possible, otherwise the whipped cream will slide around and the stacks will topple.)
Use an offset spatula to spread a light layer of whipped cream on the bottom melon slice, and gently place the second slice on top. Spread another layer of whipped cream, and place the third layer on top. (Repeat for fourth layer if using four colors). Top with a swirl of whipped cream.
Repeat for remaining rainbow melons dessert stacks. Serve immediately.