Bring a large pot of water to a rolling boil. Add a generous pinch of salt. Cook the pasta according to package instructions until al dente (usually 8–11 minutes depending on type). Reserve 1 cup of pasta cooking water, then drain the pasta.

While the pasta cooks, heat olive oil in a large skillet over medium heat. Add the chopped onion and sauté for 5–7 minutes until soft and translucent.

Add the minced garlic and cook 30–60 seconds until fragrant — don’t let it brown.

Stir in the tomato paste and cook 1–2 minutes to deepen the flavor.

Pour in the crushed tomatoes, add oregano, sugar (if using), and red pepper flakes. Stir and bring to a gentle simmer.

Simmer uncovered for 12–15 minutes, stirring occasionally, until the sauce thickens slightly.

Tip: If it gets too thick, add a splash of the reserved pasta water.

Stir in the baby spinach and cook 1–2 minutes until wilted. If using cooked protein (chicken, chickpeas, shrimp), add it now to warm through.

Add the drained pasta to the skillet with the sauce. Toss well to combine, adding up to 1/2 cup reserved pasta water to create a glossy sauce that clings to the pasta. Simmer together for 1–2 minutes.

Remove from heat and stir in fresh basil and Parmesan (and butter or cream, if using).

Taste and adjust salt and pepper.

Serve hot with extra grated Parmesan, a drizzle of olive oil, and a sprinkling of fresh basil.