In a heavy saucepan over low medium heat combine rhubarb, strawberries and water.

Cover and cook until the fruit is completely defrosted and soft, approximately

7 to 9 minutes.

Pure mixture with a hand blender or in a blender, returning mixture to pan.

Increase heat to medium and add Splenda. Stir to dissolve.

Add lemon juice and continue stirring until the mixture is reduced by about 1/3 and the sauce appears to have thickened.

Serve hot or cold.