Heat and mash - Place ingredients in a small saucepan over medium heat. As it heats up, the raspberries will release liquid. Once the liquid is simmering and the raspberries soften, mash them up with a fork.
Simmer for 3 minutes. Puree with stick blender (you can do this in the saucepan if the head of the stick blender is submerged, else, transfer mixture to a jug).
Strain into a bowl (optional), pressing out as much coulis as you can. Discard seeds.
Cool fully on the counter then refrigerate until required, it will thicken. Once cool, you can thin with a little water if needed. Typically served cold, but it can also be used warm!
