Nutrition per serving may change if servings are adjusted.
1 pint blueberries, divided
1/4 cup sugar
1 1/2 teaspoons lemon juice
1 tablespoon water
2 tablespoons eau-de-vie de framboise, or Chambord (optional)
1 cup raspberries
Combine 1 1/2 cups blueberries with the sugar, lemon juice and water in a large heavy saucepan. Cook over medium-low heat, stirring constantly, until the berries pop and a sauce forms, 5 to 10 minutes.
Remove the pan from the heat and stir in framboise (or Chambord), if using. Transfer the sauce to a bowl, cover and chill until cold.
Just before serving, stir in the remaining blueberries and raspberries.