Heat your pot to medium.
Add beef and break it up with a spatula. Season with 1/2 tsp salt and black pepper. Cook until you have browned crumbles with no pink remaining. Remove beef from the pot and set aside. Drain some excess fat in the pot if desired.
Add onions and peppers and season with remaining 3/4 tsp salt, more black pepper, and cayenne pepper. Cook for 8-10 minutes, stirring occasionally, until softened.
Add garlic to the pot and cook for 1-2 minutes or until just fragrant. Stir frequently to prevent burning.
Add cooked ground beef back to the pot with beef broth, milk, Worcestershire sauce, and uncooked pasta. Stir, and gently press your ingredients down with a spatula until everything is mostly submerged in the broth.
Keep your heat at medium. Cook for 10-15 minutes, uncovered, or until pasta is cooked and most liquid has been absorbed. Stir occasionally to prevent sticking. The exact amount of liquid and cooking time depends on your pasta brand and pot size. Make sure noodles stay mostly submerged and watch things closely. Reduce heat if needed to maintain a gentle boil.
Turn off the heat. Stir in both cheeses and cover. Let your pasta rest for 5-minutes and stir again. If there's excess liquid, let rest for another 5-minutes.
Transfer to serving dishes and top with freshly cracked pepper, more parmesan, and/or crushed red pepper flakes.
Calories: 461kcal, Carbohydrates: 47g, Protein: 31g, Fat: 15g, Saturated Fat: 7g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 5g, Trans Fat: 0.5g, Cholesterol: 69mg, Sodium: 1165mg, Potassium: 527mg, Fiber: 7g, Sugar: 7g, Vitamin A: 1476IU, Vitamin C: 53mg, Calcium: 191mg, Iron: 2mg