Brown the Ground Beef: In a large skillet or Dutch oven, heat over medium-high heat and add 1 pound of ground beef. Cook for about 5-7 minutes, breaking it up until browned. Drain excess grease.

Sauté the Vegetables: Add 1 chopped onion and 1 chopped green bell pepper to the skillet. Stir and sauté for 5-7 minutes until softened.

Create the Sauce Mixture: Stir in 1 can of diced tomatoes with green chilies, 1 teaspoon of Italian seasoning, ½ teaspoon of salt, and ¼ teaspoon of black pepper. Simmer on low for about 15 minutes.

Cook the Spaghetti: Cook 12 ounces of spaghetti according to package instructions until al dente, about 8-10 minutes. Drain the pasta.

Prepare the Creamy Mixture: In a mixing bowl, combine 8 ounces of softened cream cheese and ½ cup of melted butter. Blend until smooth, then mix in ½ cup of grated Parmesan cheese and ¼ cup of milk. Season with 1 teaspoon of garlic powder, ½ teaspoon of salt, and ¼ teaspoon of black pepper.

Combine Spaghetti with Creamy Mixture: Add the drained spaghetti to the creamy mixture and toss gently until coated evenly.

Layer the Casserole: Preheat oven to 350°F (175°C). In a greased baking dish, spread half of the creamy mixture, followed by half of the meat sauce, and sprinkle 1 cup of shredded mozzarella cheese. Repeat layers.

Bake to Perfection: Bake the casserole in the preheated oven for 25-30 minutes until the cheese is melted and golden brown.

Rest and Serve: Remove the casserole and let it rest for 5-10 minutes before serving.