I have roasted Hatch chiles in my freezer. In August 2011 I bought a huge burlap bag of Hatch green chiles from Bountiful Baskets. I roasted them all, then skinned and seeded them. I chopped some and left some whole. I froze the chopped ones in 1/2 c. portions, since that's about the same as a can of diced green chiles. I've used up all the chopped ones but I still have a lot of whole ones, so this will be a great way to use them up!
Roasting chiles isn't hard, but it is time consuming. Doing it on your barbecue grill is the easiest way. All you have to do is throw them on a hot grill, then turn them every once in a while until they get nice and charred all over. Once they're charred, throw them into a plastic bag and seal them up. That lets them steam a little, and it makes them easier to skin. Once they're cool enough to handle, peel the skins off and slice the chiles open and remove the seeds. That's it! You can use them right away or freeze them like I did. They're yummy!
Back to the chile rellenos casserole. I love chile rellenos. I've been wanting to make them ever since I roasted countless batches of Hatch green chiles. I'd looked at several recipes and to tell you the truth, I was just too lazy to do all that work. You have to fill each chile with cheese, then dip each one in batter, then fry them, then make a sauce to serve them with. Like a lot of things, I'm sure it's not that hard, just time consuming. At any rate, I just never tried out a single recipe. After I started to build up quite a supply of Anaheims in addition to what I already had in the freezer, I figured it was time to start using some of them up. In the past I had seen recipes for chile rellenos casseroles, but I'd never bothered to try any of them either. I was worried a casserole wouldn't live up to a "real" chile relleno, but I had to try something. I searched the internet for a chile rellenos casserole, and this is what I found. I halved the original recipe, so it could easily be doubled to make in a 13x9" pan.
Chile Rellenos Casserole
adapted from teeniecakes.com
6 roasted Anaheim or Hatch green chiles
2 c. cheese (I used colby jack and cheddar, but I think you could use whatever you have on hand)
3 eggs, separated
3/4 c. milk
3 Tbs. flour
1 1/2 tsp. olive oil
1 (14.5 oz.) can diced tomatoes, undrained
1-2 Tbs. diced onion
salt and pepper to taste for both egg mixture and sauce
Preheat oven to 325 degrees. Grease an 8x8" baking dish. Layer 3 chiles, then 1 c. cheese, then 3 chiles, then 1 c. cheese. If you cut your chiles open and lay them out flat, they will fit the pan almost perfectly. Beat egg whites until stiff peaks form. In a small bowl, mix egg yolks, milk, flour, and salt and pepper to taste. Fold in egg whites. Pour over chiles and cheese. Bake for 45 minutes or until golden brown.
While chiles are baking, puree the diced tomatoes in a blender. Heat olive oil in saucepan over medium heat. Add onions and saute until translucent. Add pureed tomatoes and simmer over medium-low heat until slightly thickened, about 15 minutes. Spread evenly over the casserole and bake for an additional 30 minutes. Remove from oven and let it stand 5-10 minutes before serving.