Cheesy Tex-Mex Beef Tortilla Bake

Heat a drizzle of oil in a large, heavy-bottomed pot over medium-high heat. Add beef, scallion whites, and garlic; cook, breaking up meat into pieces, until browned and cooked through, 4-6 minutes. Carefully drain any excess grease from pot. Add Tex-Mex paste, stock concentrate, and Southwest Spice Blend; stir to combine.

Stir corn, black beans, and crushed tomatoes into beef mixture until combined. Season with 1½ tsp salt and pepper. Spread one-third of the beef mixture in an 8-by-8-inch baking dish in an even layer (use 3 tsp salt and a 9-by-13-inch baking dish for 8 servings). Arrange four tortilla halves in a single layer over the beef mixture, then top with one packet of cheese (eight tortilla halves and two packets of cheese for 8). Repeat two more times with remaining beef mixture, tortillas, and cheese.

Coat one side of a large piece of aluminum foil with nonstick cooking spray. Cover baking dish tightly with aluminum foil, coated side down, and place on a baking sheet. Bake on middle rack until cheese melts and filling is hot and bubbling, 10-12 minutes.