In a mason jar or airtight container, combine the rolled oats, milk, Greek yogurt, peanut butter, mashed banana, honey, vanilla extract, and sea salt.
Stir vigorously with a spoon or shake the sealed jar until the peanut butter is fully incorporated and no clumps remain. The mixture should look evenly creamy.
Seal the container tightly and refrigerate for at least 4 hours, or preferably overnight. The oats will absorb the liquid and soften to a pudding-like texture.
Before serving, give the oats a good stir. If the consistency is too thick, add 1-2 tablespoons of milk and stir until you reach your desired thickness.
Top with fresh banana slices, a drizzle of peanut butter, chopped peanuts, chia seeds, or dark chocolate chips as desired.
Enjoy cold straight from the jar, or microwave for 45-60 seconds if you prefer warm oats.
