Amish Baked Oatmeal

I whipped this up last night and baked it today after church so it sat in the fridge overnight. I made it in a 9x13 greased pan.

2/3 cup butter
4 large eggs
1 1/2 cups brown sugar
3 tsp. baking powder
3 tsp vanilla
1 tsp nutmeg
1 tsp cinnamon
dash of salt
2 cups milk
6 cups oatmeal

Mix it all together and put it in a 9x13 (greased) pan and let it sit overnight. The next morning just bake it at 350 for about 40 minutes and it's good to go. My family absolutely loved it!