Heat olive oil in a saucepan over medium heat. Sauté onion 5–7 minutes until soft and translucent.
Add garlic; cook 30 seconds until fragrant. Stir in tomato paste; cook 1–2 minutes to caramelize.
Add crushed tomatoes, water, oregano, dried basil, bay leaf, red pepper flakes (if using), salt, pepper, and sugar (if using).
Bring to a gentle simmer, partially cover, and cook 20–30 minutes, stirring occasionally, until thickened and flavors meld.
Remove bay leaf. Stir in butter (optional) and fresh herbs. Adjust salt/pepper.
For a smoother texture, use an immersion blender briefly. Toss with hot pasta, using a splash of pasta water to help it cling. Enjoy!