Preheat oven to 400F. Lay croissants on cookie sheet and bake until golden brown, 6 minutes. Let cool.
Cook onion and shallot in a T. oil i a skillet a few mins and let cool.
In a large bowl, whisk together eggs, milk, heavy cream, chives and paprika. Season with salt, pepper and cheeses.
Lay croissants, bacon and onion into a greased 9x13 dish.Pour egg mix on top and press down gently to fully soak croissants. Cover with plastic wrap and rest in fridge until morning.
In the morning, preheat oven to 350F. (Can top with more cheese, if desired)Bake casserole 40-45 mins until golden.Top with parsley and serve!