Sauté the onions in oil in a large saucepan until they begin to caramelize. Reduce heat slightly and add garlic (and basil if you are using the dried herb). Continue to sauté for a few more minutes until the basil and garlic are fragrant. Deglaze with half the wine and reduce.
Cut your tomatoes into pieces, and add along with any liquid to the onions. If you desire, add tomato paste for a thicker sauce and richer color. I use about three ounces.
Cook uncovered at medium-low heat for about 40 minutes. Stir infrequently, so enough liquid cooks out. If your tomatoes are not especially ripe or too acidic, add a dash of vegan sugar to cut back the tartness.
Add the rest of the wine and fresh basil (if you have not already added dried basil). Cook uncovered for 15-20 minutes more until the alcohol is cooked out and the sauce thickens up again.
Check for seasonings. Add some pepper to taste and serve over pasta.