Start by cooking the pasta in a large pot of boiling, salted water. Cook it just until al dente, about a minute less than the package instructions. This ensures it finishes cooking perfectly in the sauce.
In a large skillet, heat olive oil over medium-low heat. Sauté the onions and garlic for a couple of minutes until fragrant. Then, add the ground beef and season with salt, pepper, paprika, oregano, and chili flakes. Cook until browned, breaking it into small pieces.
Stir in the roasted bell peppers, then pour in the chicken broth and crushed tomatoes. Add the tomato paste and simmer for about 10 minutes. This lets the flavors meld and the sauce thicken slightly.
Lower the heat, stir in the cream, and toss in the pasta. Let it cook for 1-2 minutes until everything is coated in the luscious sauce. Finally, add the cheddar and stir until melted. Serve immediately with grated Parmesan and fresh thyme if desired.