We've all been there. Scouring through the bits and pieces of leftovers, wondering "what to make?" On a work night, when you're getting home late you don't want to spend an hour and a half preparing dinner and in any argument between you and the oven that's older than you, the oven is going to win.
Brown the ground beef and half an onion, drain and stir in about 1/2 cup of water and one package of low sodium taco seasoning mix (or make your own mix with a Tablespoon of chili powder and 1/2 tsp each of garlic powder, onion powder, dried oregano, cumin, hot and smoked paprika and a dash of black pepper and sea salt). Simmer until the liquid is absorbed, but the meat is still slightly wet, stirring occasionally.
Cream of Cluck Soup to have on hand in the freezer for such recipes, it's cheaper without all the salt of canned) a can of Rotel (diced tomatoes and green chilis) and a shake or two of crushed red pepper.
Place half of the sauce mixture in the bottom of an 8 x 8 or 10 x 10 casserole.
Place on sauce, cover with remaining sauce and a handful of shredded extra sharp cheddar. Cover with foil and heat at 350 for about 25-30 minutes. Top with sour cream or onions or chopped pepper, whatever suits your fancy. Add some raw baby carrots and chips to scoop up any remaining sauce.