In a large mixing bowl, combine rolled oats, milk, pumpkin purée, chia seeds, vanilla extract, pumpkin pie spice, and maple syrup. Stir until well incorporated.

In a separate bowl, blend Greek yogurt (or cream cheese) with additional milk and maple syrup until smooth and creamy.

Spoon half of the oat mixture into a mason jar or container. Add a layer of the cheesecake mixture, followed by the remaining oat mixture.

Cover the jar and refrigerate for at least 4 hours or overnight.

The next morning, stir the oats gently. If desired, add a splash of milk. Top with graham crackers, cinnamon, and maple syrup.