In a large mixing bowl, add oats, chia seeds, Greek yogurt, and non-dairy milk. Mix in maple syrup and vanilla extract. Fold in diced apple and ground cinnamon until fully combined.

Cover the bowl tightly and refrigerate for at least 2 hours, preferably overnight.

After chilling, stir the mixture and divide into four jars.

Add toppings such as nut butter, nuts, or fresh fruit before serving.

Store any leftovers in an airtight container in the fridge for up to 5 days.