Preheat the oven to 350˚F. Lightly grease a 9x13 inch baking dish and set aside.
In a large bowl, mix together the oats, sugar, baking powder, salt, cinnamon and chia seeds. Add in the milk, applesauce, eggs and vanilla until smooth.
Pour the oatmeal into the prepared baking dish and bake in the preheated oven for 25-30 minutes, or until edges are golden brown.