Roast green chile by placing chile's on a sheet pan and broiling in oven until charred. Turn peppers every few minutes until charred on each side. When charred, place in a plastic bag and let steam for 5 minutes. With hands, remove blacken skins. Then slice off the tops to remove seed pods and veins. Rough chop chiles.
Or use canned Hatch Chile Peppers. 8 ounces.
In a large pan, cook the sausage and onions together until the sausage is done. Drain grease from sausage if needed. Add the chopped green chiles and stir until combined. Let cool slightly.
Transfer sausage/onion/chile mixture to a large bowl and fold in two cups of the cheese.
Spray a 9 x 13 casserole dish with PAM.
Use a 1/3-cup measuring cup to scoop out sausage/cheese/chile mixture onto a tortilla. Roll up tortilla and place seam side down in the baking dish. Repeat until all the tortillas are squeezed into the pan.
Whisk together half-and-half, eggs and flour. Pour over tortillas. Cover and let sit in refrigerator overnight.
In the morning, preheat oven to 350ºF. Bake, covered, for 30-40 minutes, or until eggs are set.
Sprinkle remaining 1/2 cup of cheese over burritos and bake, uncovered for 10 more minutes, or until the cheese is melted.
Serve with salsa and sour cream.