Boil the pasta. Bring a large pot of salted water to a boil. Cook the high-protein pasta according to package directions until just al dente. Reserve 1 cup of pasta water, then drain.

Brown the sausage. While the pasta cooks, heat 1 tbsp olive oil in a large skillet over medium-high. Add the sausage, breaking it into small pieces with a spoon. Cook until well browned and cooked through, about 6–8 minutes. Transfer to a plate and drain excess fat if needed.

Sauté aromatics. In the same skillet, add another drizzle of olive oil if the pan looks dry. Add diced onion and cook 3–4 minutes until softened. Stir in garlic and cook 30–60 seconds until fragrant.

Build the sauce. Add tomato paste and cook 1 minute, stirring. Pour in crushed tomatoes and chicken broth. Season with Italian seasoning, red pepper flakes, salt, and pepper. Simmer 5–7 minutes to thicken slightly.

Add the greens. Stir in baby spinach and let it wilt into the sauce, 1–2 minutes. Return the browned sausage to the pan and stir to combine.

Make it creamy. Reduce heat to low. Whisk the Greek yogurt in a small bowl with 2–3 tablespoons of warm sauce to temper it. Stir the tempered yogurt into the skillet until smooth. If the sauce is too thick, add a splash of reserved pasta water.

Toss with pasta. Add the drained pasta to the sauce and toss until evenly coated. Sprinkle in Parmesan and toss again. Adjust seasoning with salt and pepper. Add more pasta water as needed for a silky finish.

Finish and serve. Top with fresh basil or parsley and an extra pinch of red pepper flakes if you like heat. Serve warm with a side salad or roasted vegetables.