Courtesy of Lauren Chattman from her cookbook "Icebox Pies"
Two ways that I love to top my sponge pies are raspberry coulis and mango coulis. All coulis is, is a very simple fruit sauce consisting of pureed fruit, a little bit of confectioner sugar, and maybe some lemon or lime juice. To make raspberry coulis, all you need is a 12oz. bag of raspberries, 1/4 cup of confectioner sugar, and 1 tablespoon of lemon juice. You whip them up in the food processor and push through a strainer to get rid of the seeds.
Mango coulis is the same thing; a 14oz. bag of frozen mango puree, 2 tablespoons of confectioner sugar, and 1 tablespoon of fresh lime juice. These are both just wonderful over any kind of icebox pie. They both have a bright, fresh fruit flavor that contrasts really well with some of the richer whipped-cream fillings that I like to pour into pie shells.