Heat a couple tablespoons of oil in a heavy bottomed pot. This recipe yields a lot of sauce so make sure your pot is large enough for the volume of the tomatoes. Sweat the onions and garlic until softened. Be care not to let them burn; turn down your heat if they start to brown. Add Italian seasoning to the onion/garlic and incorporate well.
Add tomato paste and mix through. Cook the paste for about a minute.
Add the red wine. Once incorporated, add both cans of tomatoes and the two bay leaves.
Then add sugar, salt, and pepper. Note that the amount of sugar will depend on how acidic your tomatoes are, which will vary from brand to brand and even batch to batch, so adjust accordingly. Add the salt and pepper to taste. You may want to add less at this stage and adjust the amount at the end.
Bring to a boil then down to a simmer. Cover it and let the sauce cook over low heat, simmering for at least an hour up to 3 hours. I cook this sauce low and slow, usually for a 2-3 hours.
Check and stir the sauce occasionally to make sure it isn't burning or sticking to the bottom of the pot. Turn down the heat if it is boiling too rapidly. After it's done simmering, remove the bay leaves and blend the sauce to smoothness with a hand blender (if desired). Taste and make final adjustments to sugar, salt, pepper.
Serve with pasta or use it as a base for other recipes requiring red sauce!