water
1 (20 ounce) can blueberries, drained
1/2 cup sliced fresh strawberries
1/4 cup onion juice
Place blueberries, strawberries, onion mixture and juice in large container or plastic freezer bag. Freeze overnight.
Preheat an outdoor grill for high heat. Position orange juice bowl in center of grill. Grill burgers, uncovered, for 5 to 6 minutes per side. Cool.