Chile Rellenos Casserole

2 - 7 oz cans whole chiles OR 1 1/4 lb. fresh roasted Hatch chiles
1 lb. shredded cheddar cheese
1 lb. shredded jack cheese
4 eggs separated
2/3 cup evaporated milk (small can - 5 1/4 oz)
1 Tbs flour
1 Tbs sugar
1/2 tsp salt

Preheat oven to 350 degrees. In a 9x13 baking dish, alternate chiles and cheese to make 2 layers each.
Beat eggs whites until stiff. In a separate bowl, beat egg yolks until foamy, then add evaporated milk, flour, sugar & salt. Fold in egg whites into yolk mixture. Pour combined mixture over chiles and cheese. Back for 50 minutes at 350 degrees.