Brown ground beef, adding chopped onions near the end. Then add 1/3 of enchilada sauce. I sprinkle just a touch of cinnamon to sweeten the sauce. A lovely Hispanic woman taught me this trick!
Warm the tortillas in a pan or on the grill to make them pliable. You could probably use the microwave, I don't because I'm afraid they'll get tough. Take one tortilla in the end of your 8x10, (or 9x12 if you want more) baking dish, folded with open sides up & facing you, put 2-3 Tablespoons of the grated cheese, then the 2-3 Tablespoons of the beef mixture & roll seam side to bottom of pan. Continue until all shells are in the pan, then cover with the rest of the cheese & remaining enchilada sauce.
Bake at 375 degrees for 30 to 45 minutes, depending on how crisp you want the top. Serve with sour cream for garnish, re-fried beans & a salad. Dinner is served ;)