In a mason jar or container, combine the rolled oats, chia seeds, cinnamon, and salt. Pour in the milk and stir well to combine, breaking up any clumps in the oats. Add the peanut butter, yogurt, maple syrup, and vanilla extract. Stir thoroughly until everything is well incorporated and the mixture has a uniform consistency—I like to use a fork to ensure the peanut butter is fully integrated and there are no pockets of unmixed ingredients.

Cover the jar with a lid and refrigerate for at least 4 hours, though overnight (8+ hours) is ideal. The oats and chia seeds will absorb the liquid and soften, while the flavors meld together. I find that letting it sit overnight creates the best texture—creamy and custard-like rather than soupy.

Remove the jar from the refrigerator and give it a good stir. If the mixture seems too thick, add milk 1 tablespoon at a time until you reach your desired consistency—overnight oats should be spoonable but creamy, not dry. Divide between bowls and top with fresh fruit, optional granola, chopped peanuts, or an additional drizzle of peanut butter if desired.