1. Combine blueberries and sugar in a saucepan. Bring to a boil, stirring to break up fruit. Reduce to a simmer, and cook 5 minutes. Remove from heat, and working in batches, puree mixture. Pour through a fine sieve into a bowl (you should have 1 1/2 cups). Refrigerate until cold, about 30 minutes.

2. Reserve 2 tablespoons for coulis. Freeze remaining mixture in an ice cream maker according to manufacturer's directions, then transfer directly to bombe mold.