Place pitted and halved cherries into a small sauce pan with water, sugar and lemon juice. Bring mixture to a boil over medium heat. Cook until cherries are soft (about 5 minutes).
Remove cherries from the heat, transfer to a blender or food processor and purée, scraping down the sides if needed. Strain through a fine meshed strainer to ensure a smooth sauce. Refrigerate the coulis covered for up to 3 days.