Optional toppings: additional peanut butter, yogurt, pure maple syrup, diced apple
Preheat oven to 375*F
Grease a 8×8 baking dish (you can use smaller or larger but cooking times will vary. For a smaller pan, you will have to bake longer to ensure it’s fully cooked in the center).
In a large mixing bowl, combine egg, milk, brown sugar, peanut butter and vanilla.
In a separate mixing bowl, combine oats, baking powder, cinnamon, chia seeds and salt
Add dry to wet mixture, folding gently to combine, then fold in apples. Let sit for 2 minutes to allow chia seeds to soak up some of the moisture
Pour into greased baking dish using a spatula to spread the mixture evenly throughout the dish
Bake for 30-40 minutes until golden brown (because every oven is different, I recommend plunging a knife or cake tester into the center of the dish to test if it’s done, if it comes out clean or just a bit wet, it’s done).
Allow to cool completely before slicing. You don’t HAVE to wait, but note that the squares may fall apart a bit if you’re scooping it out of the dish right when it comes from the oven.
Oats keep well in an airtight container in the fridge for up to 5 days. Reheat in the microwave before serving or serve cold.