Place nonfat plain greek yogurt, grape juice, and powdered peanut butter in either a quart size zip top bag or a mason jar. Shake it up to combine ingredients. Set aside for a moment.
Fill a gallon size zip top bag about halfway to the top with ice. Add about 1/3 cup salt and shake up for a few seconds.
Take bag or jar with yogurt mixture and place inside the gallon size bag, and seal the top.
Shake, shake, shake! Shake the gallon size bag for about 10 minutes, or until your ingredients in the smaller bag/jar turn to frozen yogurt consistency. (Note – it will be quicker if your yogurt mixture is in a bag versus a jar).
Scoop frozen yogurt into a bowl and enjoy!
Notes
Nutrition Facts (approximate; assumes use of powdered peanut butter):189 calories, 1 g fat, 0 g sat fat, 0 g trans fat, 118 mg sodium, 21 g carbohydrate, 1 g fiber, 15 g sugar (0.5 g added sugar = 0.125 teaspoons), 24 g protein, Vitamin A: 0%, Vitamin C: 40%, Calcium: 17%, Iron: 2%