Stir together the raspberries and sugar in a heavy saucepan. Bring the mixture to a boil over medium heat and cook at a rolling boil for 7-8 minutes, stirring often, until the sauce is slightly thickened.
Pour the finished sauce into a heatsafe bowl or glass measuring cup to cool to room temperature before refrigerating until chilled. Serve on top of ice cream or cheesecake or whatever you would like! Enjoy!
Notes
For best freshness, store sauce covered in the refrigerator for up to 5 days.