Heat a large pot over medium heat. Add the ground beef and diced onion, cooking until
the beef is browned, about 5 to 7 minutes. Drain any excess fat.
Stir in the garlic powder, black pepper, red pepper flakes, and tomato paste. Cook for 1
to 2 minutes to enhance the flavor.
Pour in the beef broth and milk. Stir well, then add the protein pasta. Bring to a
simmer, cover, and cook for 8 to 10 minutes, stirring occasionally.
Stir in the roasted red peppers and spinach. Once the pasta is cooked and the sauce
thickens, turn off the heat and mix in the shredded cheddar until melted.
Serve immediately