Hull the strawberries and mash with the back of a fork (if using frozen, defrost first). Stir in the strawberry jam.
Place a few tablespoons of the oats into 2 mason jars. Top with half of the mashed strawberries. Top with the remaining oats followed by the mashed strawberries and peanut butter. Keep in the fridge overnight.
In the morning, top the oats with the extra fresh strawberries, if desired, and serve.