Small-Batch Tomato Soup (Gluten-Free)

Because it is apparently impossible to find gluten-free tomato soup for anything less than $5.00 per meal, I offer the following recipe:

Small-batch tomato soup

Ingredients: 

1 small can tomato paste (6 oz, or about 1/3 cup)
1/2 small onion (approx 1/3 cup chopped)
2 cloves garlic, minced
1/2 teaspoon dried basil or 1 tsp fresh, finely chopped
1 tablespoon unsalted butter or olive oil
2 cups vegetable stock (or 2 tsp Better than Bullion vegetable base and 2 cups hot water)
Up to 1/2 cup heavy cream or whole milk (to taste)
You may also need up to 1/4 tsp baking soda
Optional:  1/2 cup canned diced tomatoes, salt-free, if you like "chunky" soup

Melt the butter (or heat the oil) in the bottom of a medium size pot on medium heat
Sautee the onion and garlic until soft
add the basil
continue to sautee until browned
add the tomato paste and vegetable stock
If you want chunky soup, add the canned diced tomatoes
stir well to combine
simmer for 20-30 minutes
taste the mixture.  If it is too sour or acid, add 1/8 teaspoon baking soda and stir well while it foams.  Wait one minute and taste again, adding another 1/8 tsp if necessary.  The soda will neutralize the acidity of the tomatoes, but too much will make the soup bland. 
let soup cool slightly, then stir in cream or milk to whatever preference you have for creaminess. Start with 1/4 cup, taste, and increase as needed.  I have not tried substitute milks (soy, coconut, rice, etc.) and do not know how they behave, but since you're not "cooking" the milk, I suspect it would work just fine.