Add 1 1/2 cups frozen wild blueberries and 1 tablespoon water to a large microwavable bowl and heat for 2-3 minutes on high. The berries should look goopy. (You may also warm them on the stove.)
Once heated, add 4 teaspoons of chia seeds to the bowl, stir well, and set in the refrigerator to chill for 15-20 minutes. The chia seeds will form a gel and thicken up the blueberries into a jelly-like texture.
While the blueberry jam is chilling, set out 4 jars (12.5 oz or larger) and fill each jar with 1/2 cup rolled oats and 1 teaspoon chia seeds.
In a blender, add 3 cups unsweetened vanilla almond milk, 4 dates and 2 tablespoons peanut butter, and blend until well combined.
Evenly pour the almond milk mixture into the 4 jars and stir well.
Once the blueberry chia jam has thickened in the refrigerator, evenly spoon it into the four jars.
Then cover with a lid and refrigerate overnight, or at least 6 hours, before serving. This recipe keeps for up to a week in the fridge and can be made a few days ahead of time.