Makes about 1 3/4 cups
2 pints of fresh or frozen raspberries, about 1 pound (ora mixture of raspberries and strawberries
1/4 cups of sugar, or to taste, depending on the taste of the berries
1 tablespoon fresh lemon juice
2 to 4 tablespoons Creme de Cassis, according to your taste (substitute 1/4 cup of water)
Place all ingredients in a medium sauce pan and simmer over medium heat until the berries break down, about 10 to 15 minutes. Taste while the berries are cooking and adjust sugar if necessary. Let cool for about 10 minutes.
Strain the sauce through a fine sieve or chinois over a bowl. Use the back of a spoon (a rubber or silicon spatula works well) to push on the fruit. Make sure that you push as much of the fruit through as you can. Scrape off the bottom of the sieve and discard any pulp and seeds that remain in the sieve.
Allow the coulis to come to room temperature before serving. The sauce can be stored for several days in the refrigerator.