1) Preheat oven to 400˚ F. Roughly chop tomatoes and onion. spread out on a large sheet pan with sides or roasting pan. Drizzle with olive oil.
2) Slice off the top of the head of garlic so that the cloves are exposed. Drizzle exposed cloves with olive oil and place cut side down on pan with tomatoes and onions and place pan in hot oven.
3) Roast the tomatoes, onion and garlic until the tomatoes are starting to brown and the garlic is tender, about 40 to 50 minutes. Remove from oven.
4) Spoon or slide tomatoes and onions into a blender with salt, pepper, white beans, seasonings, fresh herbs and baking soda. Squeeze the cloves of garlic from the head into the blender. Puree until smooth.
5) Transfer the soup into a pot and add vegetable stock or broth if a thinner consistency is desired. Add 1/8 tsp of baking soda to neutralize the acidity of the tomatoes and stir. Bring to a boil and then simmer on low for about 20 minutes.
6) Divide the soup into bowls and top with the freshly grated Romano or Parmesan cheese and fresh thyme. Enjoy!