Chef's Notes
It is important to cook the onions until soft before adding the tomatoes, otherwise, the acidity in the tomatoes will impede the softening of the onions.
The baking soda will foam up a bit and then subside, which proves that it is active. Adding a bit of baking soda will neutralize the acid in the tomatoes, which prevents the milk from curdling.
You can roast the tomatoes and onion in the oven before proceeding with the recipe; you can also add some garlic, carrots, celery, sun-dried or oven-dried tomatoes. But I like the simplicity of just using minimal ingredients for this soup. So, it is important to use locally and seasonally grown tomatoes for the best flavor.
Tomatoes are high in lycopene which protects your skin from sunburn. However, if you have arthritis, avoid tomatoes.
If you are lactose intolerant, omit baking soda and milk. Proceed with recipe. Just garnish with natural yogurt instead of Parmesan cheese. But if you still want to use milk, take lactase enzyme with the meal to help you digest the lactose in the milk.
Step 1: Cooking the onions
- 2 T Extra virgin olive oil
- 2 T Unsalted Butter
- 1 medium onion, diced
Peel and dice the onions. Heat a heavy pot over medium heat. Add the oil and butter. When the butter is melted and hot enough to sizzle, add the onion. Lower th heat and sweat until transparent and soft but not brown, about 7 to 10 minutes.
Step 2: Cooking the rest of the soup
- 2 lbs very ripe Roma tomatoes
- 2 fresh thyme sprigs
- 1 tsp sea salt
- 1/4 tsp baking soda
- 250 ml (or more) chicken or vegetable stock
- 250 ml whole milk
While the onions are cooking, cut the tomatoes into chunks and then add these along with the thyme, salt, baking soda and 100ml of stock or less. Bring to a boil, stir in milk, reduce heat to low, cover and simmer until the mixture thickens and the tomatoes are tender, about 10 to 15 minutes.
Remove from the heat. Remove and discard thyme sprigs.
Step 3: Pureeing the Soup
Cool the soup slightly. Set aside about a cup of the broth to prevent the soup from being too liquid after blending.
Working in batches, puree soup in blender until smooth and strain the soup into a pot, making sure to push through the solids to extract the liquid from the puree. You may add more broth or stock to the soup if needed.
Step 4: Sauteeing the mushrooms
- 1 cup oyster mushroom
- Butter, sea salt and black peper
- Parmigiano-Reggiano
- Fresh basil leaves
While the soup is reheating over low heat to serving temperature, dice and saute the oyster mushrooms in a little bit of butter and season with a little bit of salt and pepper. Then grate the cheese and chiffonade the basil leaves.
Step 5: Serving the Soup
Taste the soup and adjust the seasoning with sea salt. But not too much as the soup will be garnish with some Parmesan cheese. Ladle into bowls, and garnish with the cooked mushrooms, grated cheese and basil leaves.
Serve with rye bread or olive focaccia bread.