5 C. seeded, cubed watermelon 2 C. 1% milk, divided use 1 pkg. (3 oz.) watermelon flavored gelatin powder 1 container (8 oz.) fat-free plain yogurt 3 pkgs. (4 oz. each) vanilla ice cream mix 1 tsp. vanilla extract 1 tsp. butter flavoring 2-3 drops red food coloring (optional)
Place watermelon, 1 cup of the milk and gelatin powder in a blender. Process until smooth. (It may be necessary to process in two batches to avoid overflow.) Pour this mixture into the freezer can of a 1-gallon hand-turned or electric ice cream freezer. Add remaining milk, yogurt, ice cream mix, vanilla extract, butter flavoring and food coloring to blender. Process until smooth. Add this mixture to watermelon mixture. Stir to combine. Freeze according to manufacturers instructions. Note: If using an electric freezer, the unit may not stop once the mixture is frozen. Check sherbet after 20-30 minutes of processing.