1. In a small stockpot melt butter and sugar on Medium heat and stir until well blended.
2. Add triple berry blend and stir occasionally for 5 minutes.
3. Mix cornstarch with water and add to the berry mixture. Stir.
4. Simmer for another 5 minutes, then remove from heat.
5. Transfer syrup to bowl and serve warm, or cool in refrigerator to serve cold.
Note: Syrup can be made 1 day ahead. Cover and refrigerate.