Recipe Source: Baking: From My Home To Yours by Dorie Greenspan, page 467
1 pint (2 cups) red raspberries - fresh or frozen, partially thawed if frozen (I used one container of blackberries)
3 tablespoons sugar, or more to taste
Directions: Put the berries and sugar in a blender or food processor and whir until pureed. Taste and mix in more sugar if needed. Press the coulis through a strainer or a food mill to eliminate the seeds.
Playing Around: Using the same technique, and adjusting the sugar to taste, you can make other fruit coulis. Instead of raspberries, use blueberries, strawberries or exotic fruits like passion fruit, mango or pineapple.