1. Prepare Your Apple: Start by washing and peeling your apple, if desired. Then, finely dice half of the apple into small, uniform pieces. Aim for about 1/2 cup of diced apple. Small pieces will soften more effectively overnight and distribute the flavor throughout the oats.

2. Combine Dry Ingredients: In a jar (a 16-ounce mason jar works perfectly) or a small container with a lid, combine the rolled oats, chia seeds, apple pie spice, and a pinch of salt. Stir these dry ingredients together briefly to ensure they are well mixed. This prevents clumping when the liquid is added.

3. Add Wet Ingredients: Pour in the milk and maple syrup (or honey) into the jar. Add the finely diced apple pieces to the mixture.

4. Stir Thoroughly: Using a spoon, stir all the ingredients together very well. Make sure there are no dry pockets of oats or chia seeds at the bottom of the jar. Stirring well is key to preventing the oats from clumping and ensuring the chia seeds fully hydrate.

5. Secure and Refrigerate: Place the lid securely on the jar or container. Transfer it to the refrigerator and let it chill for at least 4 hours, but ideally overnight (8 hours), to allow the oats to soften and the chia seeds to thicken the mixture.

6. Morning Check and Serve: In the morning, open your jar of overnight oats. The mixture should be thick and creamy. If it seems too thick, you can add a splash more milk to reach your desired consistency.

7. Add Toppings and Enjoy: Stir gently, then add any desired toppings such as extra diced apple, a sprinkle of cinnamon, chopped nuts, or a dollop of Greek yogurt for added protein and creaminess. Serve chilled and enjoy your delicious, healthy breakfast!