Three kinds of sorbet combine with pineapple-coconut ice cream in this elegant layered dessert. Remember to press down as you fill the mold to prevent air pockets from forming.
To determine the volume of your mold, fill it with water, and pour water into a liquid measuring cup. The amount of water will show how much ice cream you need for that mold. If mold is cylindrical, divide total amount of mold by four flavors; plan according to your needs. Alternatively, for a triangular or dome-shaped mold, use less sorbet on the first layer, as we did.
Beat mango sorbet in the bowl of an electric mixer fitted with the paddle attachment until soft but still holding its shape, 1 to 2 minutes. Using a spoon, place sorbet in bottom of mold, spreading it into any details of mold. A rubber spatula or offset spatula will help. Smooth top; place mold in freezer to let sorbet harden, about 1 hour.
Soften coconut sorbet as above, working in batches if necessary. Remove mold from freezer; spoon coconut sorbet in a layer over mango sorbet. Smooth top; return to freezer.
When coconut sorbet has hardened, soften strawberry sorbet as above. Remove mold from freezer; add a layer of strawberry sorbet. Freeze until hardened. Repeat process with pineapple-coconut ice cream, finishing top of mold by smoothing surface and covering with plastic wrap. Freeze until hardened, a few hours or overnight.
To unmold, fill sink with very hot water. Remove mold from freezer; dip into very hot water, 7 to 8 seconds. If using, sprinkle almonds over ice cream to keep it from slipping. Using some force, invert onto a cutting board; return bombe to freezer for 15 minutes so outside refreezes. Use a very sharp knife to cut bombe into servings.