In a large frying pan, brown the ground beef and chopped onion over medium heat until the beef is fully cooked and the onion is softened.
Add Tomato Sauce and Green Beans:
Once the ground beef is cooked, add the tomato sauce and frozen green beans to the pan.
Season with salt and pepper to taste.
Stir well to combine all ingredients.
Transfer to Casserole Dish:
Preheat the oven to 350°F (175°C).
Transfer the ground beef and green bean mixture to a casserole dish.
Cover with Cheese:
Sprinkle the grated mozzarella or cheddar cheese evenly over the top of the ground beef and green bean mixture, covering it completely.
Bake:
Cover the casserole dish with aluminum foil or a lid and bake in the preheated oven for about 30 minutes, or until the cheese is melted and bubbly.
Serve:
Once baked, remove the casserole from the oven.
Let it cool for a few minutes before serving.
Notes / Tips / Wine Advice:
Wine Pairing:
Pair this comforting dish with a medium-bodied red wine such as a Merlot or a Cabernet Sauvignon. The fruity and slightly acidic characteristics of these wines will complement the savory flavors of the beef and the richness of the melted cheese.