In a large bowl, whisk together the eggs, milk and vanilla.
Add in the oats, brown sugar, salt, baking powder, butter and chocolate chips.
Stir all the ingredients together until well combined, then pour into the prepared baking dish.
Cover and refrigerate overnight or at least 6 hours.
Preheat oven to 375ºF. Bake casserole for 30-40 minutes. The oatmeal should firm up and liquid will be absorbed.
Serve with butter and extra milk or cream.
Video
Notes
The calories shown are based on the recipe being cut into 12 pieces, with 1 serving being 1 piece of baked oatmeal. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**