Place a large baking sheet in the oven; preheat to 425 degrees F.Advertisement
Heat oil in a large skillet over medium heat. Add onion and garlic; cook, stirring, until the onion is soft, about 2 minutes. Add beef, mushrooms, chili powder, cumin, oregano and salt; cook, breaking up the beef with a spoon, until the beef is no longer pink, 4 to 6 minutes. Stir in refried beans and chiles; cook, stirring, until hot, 1 to 2 minutes.
Remove the hot baking sheet from the oven, place on a heatproof surface and coat with cooking spray. Place a tortilla on a clean work surface and spread 2/3 cup of the beef mixture along the bottom third. Sprinkle with 1 tablespoon cheese, tuck the sides over the filling and roll up from the bottom into a burrito. Place seam-side down on the baking sheet. Repeat with the remaining tortillas, filling and cheese. Generously coat the tops and sides of the chimichangas with cooking spray.
Bake the chimichangas until browned, 10 to 15 minutes. Serve topped with lettuce and salsa.
2 starch, 1 vegetable, 2 lean meat, 1/2 high-fat meat, 1 fat