Brown ground beef and onion till done. Drain well and season with salt and pepper.
Prep as many ingredients as needed.
Preheat oven to 350°
Spray 2-3 quart casserole dish, sprayed with olive oil spray.
Layer 1 can of the chopped chiles to the bottom of the pan.
Add 1 cup of cheese on top of the chiles.
Spread all the ground beef mixture on top of the cheese.
Add 2nd can of chilies on top of the meat.
Add 1 cup of cheese on top of the chilies.
Mix eggs, milk, flour, and hot sauce very well and pour over the whole pan.
Put chile slices over the top if you are using them.
Bake 40-45 minutes or till golden and set. Insert a knife in the center, if it comes out clean it is done.