Place a fine mesh sieve over a glass bowl and set it aside.

In a small saucepan, combine the raspberries, sugar, and water. Squeeze the lemon and add the juice to the pan.

Bring the mixture to a simmer over medium heat and cook for 5-8 minutes, or until it has slightly thickened. The sugar should be dissolved and the berries broken down.

Pour the mixture through the sieve and into the bowl to remove the seeds and fruit pulp that didn’t break down completely.

Cool the raspberry coulis and refrigerate it until it’s completely cooled. Store it in the refrigerator in an airtight container. It can be refrigerated for up to a week, or frozen for up to three months.