Ice Cream in a Bag This is SOOO easy and delicious! In a small Ziplock bag, put: 1/2 C. half and half (milk works too) 1 Tbps. sugar 1 tsp. vanilla Insert that bag into a larger, one gallon Ziplock filled with ice and salt. Shake the bag for five minutes.Then, remove the smaller bag which should have turned into ice cream. This totally works and it is amazing! We eat it all the time now.