In a saucepan over medium heat, combine fresh or frozen blueberries with maple syrup. Cook for about 1 minute until the blueberries soften and release their juices. Let the blueberry layer cool.

In a large mixing bowl, add rolled oats, chia seeds, and your choice of water or milk. Pour in the remaining maple syrup, Greek yogurt, vanilla extract, and a pinch of salt. Stir until well combined.

Cover the bowl or transfer to jars and refrigerate for at least 3 hours or overnight.

When ready to serve, layer the cooled blueberry mixture at the bottom of a jar and spoon the overnight oats on top.