Place four jars on a flat surface. Fill each jar with ½ cup oats, ½ teaspoon ground flax, ¾ cup milk, and ½ teaspoon vanilla. Stir to combine and top with strawberries.
Refrigerate for 8 hours or overnight.
In the morning, stir to combine. Warm-up if desired or enjoy cold.
Notes
If you are using quick or instant oats, reduce the liquid to ½ cup per jar. If you like warm oats, heat them up in the microwave for 30 seconds to a minute.