In a sauce pan, whisk together the water, sugar, cornstarch, and lemon juice.  Whisk until cornstarch is blended in and their are no lumps.

Cook over medium heat until the mixture begins to boil.  Add 1 cup of the raspberries and cook for about 1 minute until the mixture thickens.  Remove from the heat and fold in the remaining 1 cup of raspberries.

Serve sauce over waffles, pancakes, ice cream, cheesecake, crepes, etc.