Preheat and prep: Set a large, deep skillet over medium heat.
Have all your vegetables chopped and ready to go for a smooth cook.
Brown the beef: Add the ground beef to the dry skillet and season with a pinch of salt and pepper. Cook, breaking it up with a spatula, until browned and no longer pink, about 4–5 minutes. If there’s noticeable grease, drain it.
Push the beef to one side.
Sauté the aromatics: Add olive oil to the empty side of the pan, then toss in onion and bell pepper. Cook 3–4 minutes until softened. Stir in zucchini and cook another 2 minutes.
Add the garlic and cook 30 seconds until fragrant.
Build the sauce: Stir the beef and veggies together. Add diced tomatoes with their juices, tomato sauce, Italian seasoning, crushed red pepper, smoked paprika, and a small pinch of salt and pepper. Stir well.
Add pasta and liquid: Pour in the broth and bring to a lively simmer.
Add the pasta, stir, and make sure the noodles are mostly submerged. Reduce heat to medium-low.
Simmer to tender: Cook 10–12 minutes, stirring occasionally, until the pasta is al dente. If the skillet looks dry before the pasta is done, add splashes of broth or water.
You want a loose, saucy consistency.
Finish with greens: Stir in the spinach and let it wilt, 1–2 minutes. Taste and adjust salt, pepper, and heat. A squeeze of lemon perks up the sauce nicely.
Serve: Sprinkle with Parmesan and fresh herbs if you like.
Serve hot, with extra red pepper flakes on the side.