Over high heat in a medium saucepan combine strawberries, water, lemon juice, and gradually add the sugar slowly. Stir and boil for a few minutes.
Reduce the heat and simmer for 10 minutes.
Remove from the heat and use an immersion blender or a stainless-steel potato masher to puree or crush the strawberries down.
(With a medium bowl under a strainer) gently pour the sauce into the strainer. Whisk the sauce in the strainer as the juice strains into the bowl. Continue whisking until all the liquid is strained from the strawberry pulp remains.