Preheat oven to 375F, and roast tomatoes cut side up with olive oil drizzled over the tomatoes. Roast for about 45 minutes, then add the cremini mushrooms, using a spoon to use the olive oil from the pan to drizzle over the mushrooms.

Continue roasting for another 15 minutes, then remove from oven. Tomatoes should be darker, a little blistered, but not burnt. They'll be soft, almost falling apart.

Cook onions and garlic over medium heat in the cooking liquid from the roasted tomatoes until translucent.

Add 5 cups of water and add the 1/4 cup tomato paste and mix until the paste has been mixed in.

Add the tomatoes and mushrooms to the pot and stir in. Bring to a boil, then lower heat and add in basil leaves and bay leaves. Let simmer for about 20 minutes.

Remove the bay leaves, then use an immersion blender or regular blender and puree until smooth and velvety.

Add the baking soda and stir. The soup will bubble a little but then it won't taste as acidic.

Add the spices and blend to incorporate the ingredients. Adjust spices to your taste.