Combine all of the ice cream ingredients (except the grape nut) into the small plastic bag and seal the bag tightly!
With the larger gallon bag, combine the rock salt and the ice cubes. The rock salt will allow the ice cream to stay frozen longer and lower the temperature of the ice cream.
Put the liquid bag into the larger gallon bag and shake vigorously for the next 10 minutes. Don't slow down or take breaks during this time! Consistency and pace are needed to create the perfect ice cream,You may need to use oven mits on your hands as the bag will get extremely cold very quickly
Once the ten minutes are done, remove the ice cream bag from the larger gallon bag. Wipe the outside so no salty liquid gets inside the ice cream. Add in the grapenut now, but it's important to note that the grape nut will be very hard/crunchy because they did not have time to soften in the liquid. You can choose to allow the ice cream to sit in the freezer (in the plastic baggie) for the next 30 minutes to allow the grape nut to partially soften/ soak in the liquid or eat as is. When you're ready to eat, set it on the counter tip for a few minutes to thaw out.Scoop out into your favorite bowl and enjoy!
Notes
** The grape nuts will be very hard/crunchy unless you allow the ice cream to sit for a bit! Read the instructions for further advice. :D