First, I season the ground beef (or beef + sausage) with salt and pepper. Then I cook it in the skillet with the chopped onion until fully browned, making sure to break the meat into fine crumbles as it cooks. If I want an extra-smooth texture, I sometimes pulse it a couple of times in a food processor before returning to the pan.
Next I stir in the tomato sauce, tomato paste, Italian seasoning, parsley, garlic powder, red pepper flakes, Worcestershire, and sugar. I mix well to combine everything fully. Then I pour in water, stir again, and bring the mixture to a simmer.
Once simmering, I lower the heat and let the sauce cook for about 30 minutes, uncovered, so the flavors deepen and some liquid reduces. If I’m using basil, I stir in the chopped fresh leaves right before serving to preserve their brightness.