Preheat the Oven: Begin by preheating your oven to 350°F (175°C).
Cook the beef: In a large skillet over medium heat, add 1 lb of ground beef. Cook until browned, about 5-7 minutes. Make sure to break it up as it cooks.
Add Aromatics: Add 1 medium chopped onion and 2 minced garlic cloves to the skillet. Sauté for another 3-4 minutes, or until the onion is translucent.
Stir in Vegetables: Incorporate 2 cups of mixed vegetables into the skillet, cooking for an additional 5 minutes until they are tender. Season with salt, pepper, and 1 teaspoon of Italian seasoning.
Create the Sauce: Pour in 1 can of cream of mushroom soup and 1 cup of milk, stirring until well combined. Bring the mixture to a gentle simmer.
Combine with Pasta: In a separate bowl, mix 1 cup of cooked pasta with the beef and vegetable mixture. Ensure everything is evenly incorporated.
Add Cheese: Stir in 1 cup of shredded cheese until melted and mixed into the casserole filling.
Transfer to Baking Dish: Pour the entire mixture into a greased 9x13 inch baking dish. Spread it evenly.
Prepare Topping: If desired, sprinkle 1 cup of breadcrumbs over the top for added crunch.
Bake: Place the casserole in the preheated oven and bake for 25-30 minutes, or until the cheese is bubbly and golden brown.