Heat the olive oil in a large pot or Dutch oven over medium heat. Add the finely chopped yellow onion and sauté until softened and translucent, about 5-7 minutes.

Add the minced garlic to the pot and cook for another 1-2 minutes until fragrant. Be careful not to burn the garlic, as it can turn bitter.

Pour in the crushed tomatoes and stir in the tomato paste. Mix well to combine everything.

Add the dried oregano, dried basil, salt, black pepper, and optional sugar. Stir to distribute the seasonings evenly throughout the sauce.

Bring the sauce to a simmer, then reduce the heat to low, cover the pot, and let it cook for at least 30 minutes, stirring occasionally. This simmering time allows the flavors to meld and deepen.

For a smoother sauce, you can use an immersion blender to blend it to your desired consistency. Alternatively, you can leave it chunky.

Stir in the fresh basil leaves just before serving for a burst of fresh flavor and aroma.

Taste and adjust seasoning with more salt and pepper if needed. Serve hot.