Adapted from Food Network Kitchens
Heat the olive oil in a stock pot on the stove at medium heat.
Caramelize onions and garlic with the herbs, probably about 15-20 minutes.
Add butternut squash, stir and cook for about 10 minutes.
Add tomato sauce, vinegar and stock. Stir and cook for about 20 minutes, until squash is soft enough to mush with a fork against the side of pot.
Blend with hand blender in the pot or cool and transfer to a blender to blend until smooth.
Check for seasoning and serve.