Jess, I got a recipe from a friend at work who's wife, on Atkin's, made this for a potluck. It was AWESOME. Hope it helps.

Chile Relleno Casserole
Low Carbohydrate Recipe

Ingredients:
3-4 roasted green chiles, canned
Three eggs, separated
Monterey Jack cheese, sliced
A very small amount of salsa (optional)
Nonstick cooking spray


Directions:
Beat the egg whites until they are stiff. Slowly fold in the egg yolks (beaten). Pour about half of this mixture into a pam-sprayed baking dish. Carefully slit the chiles length-wise and lay them on the egg mixture. Put the sliced cheese on each open chile and cover with the remaining egg mixture. Bake in a 350-degree oven for 20 to 30 minutes until the eggs are set and lightly browned. Cut into squares and have a little salsa for dipping if desired.

*Notes: Chile Rellenos are normally made by dipping the cheese stuffed chiles into an egg mixture that contains flour and then fried. Without the flour, the egg whites are fairly fragile and break apart when fried. Almond powder may be used instead of flour in this low carb recipe, but only adds flavor and not much substance to the egg mixture.

You can use fresh chiles if you have them and roast them on the bbq. Hatch brand chiles are very firm and have about a gram of carbs per chile.

Note: You can use shortening on the pan, but the spray seems to work better to keep the egg mixture from sticking.

Recipe makes four servings.

Nutrition information per serving:
Calories 641
Protein 53g
Total Fat 43g
Sodium 748mg
Cholesterol 383mg
Carbohydrates 8g
Fiber 2g

I recommend freezing the rellenos before cooking they come out much better and less runny.