Chiles Rellenos Casserole from Cook's Country

1T - vegetable oil
1 onion - chopped fine
2 pounds - 90% lean ground beef
4 - poblano (or 6 Anaheim) chiles, stemmed, seeded, and chopped
2 - garlic cloves - minced
2t - ground cumin
1 1/4t - salt
1t - dried oregano
3/4t - pepper
1/4t - cayenne pepper
1 (10oz) can - Ro-Tel tomatoes, drained
10oz - Monterey Jack cheese, shredded (21/2 cups)
1/2 cup - all-purpose flour
3/4 cup - skim milk
2 - large egg whites

1.)  Heat oven to 450 degrees.  Heat oil in 12-inch nonstick skillet over medium heat until shimmering.  Add onion and cook until softened, about 5 minutes.  Stir in beef, breaking up meat into small pieces, and cook until no longer pink, 8-10 minutes.  Using slotted spoon, transfer beef mixture to paper towel lined plate.  Pour off all but 2T fat from skillet.
2.)  Add poblanos and cook over medium-high heat until browned, 8-10 minutes.  Stir in beef mixture, carlic cumin, 3/4t salt, oregano, 1/2t pepper and cayenne and cook until fragrant, about 30 seconds.  Add tomatoes and cook until beef mixture is dry, about 1 minute.  Off heat, stir in 2 cups Monterey Jack.  Scrape mixture into 13 x 9 baking dish, pressing into even layer.
3.)  Combine flour, remaining 1/2t salt, and remaining 1/4t pepper in a bowl.  Slowly whisk milk into flour mixture until smooth: set aside.  Using stand mixer fitted with whisk, whip ell whites on medium-low speed until foamy, about 1 minute.  Increase speed to medium-high and whip until stiff peaks form, about 3 minutes.  Whisk one-third whipped egg whites into batter then gently fold in remaining whites, 1 scoop at a time, until combined.
4.)  Pour batter oer beef mixture.  Bake until topping is light golden and puffed, about 15 minutes.  Sprinkle with remaining 1/2 cup cheese and bake until golden brown, about 10 minutes.  Let cool on wire rack for 10 minutes then serve.

Bon appetite! Innkeeper Avenue Hotel Bed and Breakfast