Place sugar and 1/4 cup water in a small saucepan; stir, and bring to boil. Simmer until all the sugar is dissolved. Let syrup cool completely. Place raspberries and syrup in the jar of a blender; puree until smooth. Pour through a fine sieve or colander into a bowl; discard solids.

Serve (or store in an airtight container, refrigerated, up to 5 days).