Heat the olive oil in a wide skillet over medium heat. Add the onion and sauté until it’s softened and just starting to brown at the edges, about 5 minutes.
Push the onion aside, drop in the garlic, and cook for 30 seconds until it smells amazing. Don’t let it burn—no one wants burnt garlic vibes.
Pour in the crushed tomatoes and the water or stock. Stir to combine, then bring to a gentle simmer.
Add sugar (if using), oregano, and basil. Season with salt, pepper, and red pepper flakes if you like a little heat. Simmer uncovered for 15–20 minutes, stirring occasionally.
Taste and adjust seasoning. If it tastes a touch bright, a pinch more sugar can help; if it’s flat, a splash more salt does wonders. Finish with chopped parsley or torn basil.
Remove from heat and serve over your favorite pasta. For extra shine, swirl in a teaspoon of olive oil right before serving.