Place a mesh strainer over a medium-sized bowl and pour raspberry purr into the strainer.
Using the back of a spoon or spatula, press the puree through the mesh strainers. Once the seedless puree is in the bowl, discard of the seeds and set strainer aside.
Add sugar and lemon juice to the bowl with puree and stir well.
Store in a covered container in the refrigerator for up to one week or freeze up to one year.