Cook the ground beef: In a large skillet or Dutch oven, brown the ground beef over medium heat. Drain excess grease if needed. Sauté vegetables: Add the onion, bell pepper, and garlic to the skillet. Cook for 3-4 minutes, or until softened and fragrant. Add liquids and seasonings: Stir in the diced tomatoes, tomato sauce, beef broth, Worcestershire sauce, paprika, Italian seasoning, salt, black pepper, and red pepper flakes. Mix well. Cook the pasta: Add the uncooked elbow macaroni to the skillet, ensuring it is submerged in the liquid. Cover and simmer over medium-low heat for 15-20 minutes, stirring occasionally, until the pasta is tender and has absorbed most of the sauce. Optional cheese topping: If desired, sprinkle shredded cheddar cheese over the top and let it melt before serving. Serve hot: Ladle the goulash into bowls and enjoy with your favorite sides.