Fill a large pot with water, add a pinch of salt, and bring to a rolling boil.
Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add 1 pound Italian sausage (casing removed if present), break it up, and cook 5–7 minutes until browned and fully cooked (160°F); drain excess grease and set aside.
Reduce heat to medium; add 1 small yellow onion (chopped) and cook 3–4 minutes until translucent.
Stir in 2 cloves minced garlic and cook 1 minute until fragrant.
Pour in 28 ounces crushed tomatoes, stir to release browned bits, and bring to a gentle simmer.
Add 14.5 ounces Barilla Protein+ Penne to the boiling water and cook 10–11 minutes until al dente.
While pasta cooks, add 5 ounces fresh spinach to the simmering sauce and stir 1–2 minutes until wilted.
Return cooked sausage to the sauce and season with 0.5 teaspoon salt and 0.25 teaspoon black pepper.
Reserve 0.5 cup pasta cooking water, drain pasta, add pasta to the skillet, and toss to coat, adding reserved water as needed.
Serve immediately topped with grated Parmesan cheese; store leftovers in an airtight container in the refrigerator for up to 3 days.