In a large skillet or Dutch oven, cook ground beef and minced onion over medium-high heat until browned. Drain grease.

Return skillet to medium-low heat and add taco seasoning and water. Stir and cook for 2 minutes until thickened.

Add black or pinto beans, refried beans, corn, and salsa to the skillet. Stir to combine and remove from heat.

Grease two 9x13-inch pans or four pie dishes with cooking spray. Spread a thin layer of tomato sauce on the bottom of each pan.

Layer tortillas to cover the bottom, then add a layer of filling and shredded cheese. Repeat layering with tortillas, filling, and cheese.

Top final layer with tortillas, then pour remaining tomato sauce on top and sprinkle with remaining cheese.

Cover pans tightly with two layers of foil. Label with name and date for freezing.

To bake: Thaw in refrigerator overnight. Bake at 350°F for 45 minutes covered, then 10 more minutes uncovered.