Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish with butter or cooking spray.

Bring a large pot of salted water to a boil. Cook the spaghetti according to package directions until al dente, about 8-9 minutes. Drain thoroughly and set aside.

While pasta cooks, heat a large skillet over medium-high heat. Add ground beef, onion, and bell pepper. Cook for 6-8 minutes, breaking up the meat with a wooden spoon, until beef is browned and vegetables are tender. Drain excess grease, leaving about 1 tablespoon.

Lower heat to medium and add minced garlic. Stir constantly for 1 minute until fragrant but not browned.

Add both cans of cream soup, the entire can of Rotel with juices, Italian seasoning, and 1 cup of shredded cheddar cheese. Stir to combine and simmer gently for 3-4 minutes until cheese melts and sauce is smooth. Season with salt and pepper to taste.

Add drained spaghetti to the skillet and toss with tongs until every strand is coated in the creamy sauce.

Transfer spaghetti mixture to the prepared baking dish and spread evenly. Sprinkle remaining 1 cup of cheese across the top.

Bake uncovered for 20-30 minutes until cheese is melted, bubbly, and starting to turn golden at the edges.

Let rest for 5 minutes before serving to allow the sauce to set.