Chiles Rellenos Casserole

Name: Chiles Rellenos Casserole
Ingredients: 1 tablespoon vegetable oil1 onion ; chopped fine; 2 pounds 90 percent lean ground beef; 4 poblano chiles ; (or 6 Anaheim), stemmed, seeded, and chopped; 2 garlic cloves ; minced; 2 teaspoons ground cumin; 1 1/4 teaspoons salt1 teaspoon dried oregano; 3/4 teaspoon pepper; 1/4 teaspoon cayenne pepper; 1 (10-ounce) can Ro-Tel tomatoes ; drained; 10 ounces Monterey Jack cheese ; shredded (2 1/2 cups); 1/2 cup all-purpose flour; 3/4 cup skim milk; 2 large egg whitesInstructions