Sauté the Aromatics:
Heat olive oil in a large saucepan over medium heat. Add the garlic and onion, sautéing until softened and fragrant, about 3–4 minutes.
Add the Tomato Paste:
Stir in the tomato paste, cooking for 1–2 minutes to enhance its flavor.
Combine Tomatoes and Spices:
Pour in the crushed tomatoes, water or vegetable broth, sugar (if using), oregano, basil, and red pepper flakes. Stir well to combine.
Simmer the Sauce:
Reduce the heat to low and let the sauce simmer uncovered for 20–30 minutes, stirring occasionally. This allows the flavors to deepen and the sauce to thicken.
Add Fresh Basil:
During the last 5 minutes of cooking, stir in the fresh basil leaves for a burst of fresh flavor.
Blend for Smoothness (Optional):
For a smoother sauce, use an immersion blender directly in the pot or transfer the sauce to a blender.
Season and Serve:
Taste the sauce and adjust seasoning with salt and black pepper as needed. Serve hot over pasta, use as a pizza base, or enjoy as a dipping sauce.