In a large mixing bowl, combine the rolled oats, Greek yogurt, and milk. Stir in the chia seeds, peanut butter, maple syrup, vanilla extract, and a pinch of salt. Use a whisk or fork to mix thoroughly, ensuring all ingredients are well blended and creamy.

Cover the bowl with plastic wrap or transfer the mixture into individual mason jars for easy storage. Place it in the refrigerator to chill for a minimum of 3 hours, or preferably overnight.

After refrigeration, remove the mixture from the fridge. Start layering oats into mason jars, filling each jar one-third full with the oats, then adding approximately 2 tablespoons of your chosen jam in the center. Top with remaining oat mixture.

Garnish each jar with an extra spoonful of jam, fresh berries, or chopped peanuts. Serve immediately or store in the refrigerator.