Create the soffritto by placing the onion, celery, carrot, garlic, and salt in a food processor, puree
Add olive to a heavy-bottomed pot with a lid over medium-high heat, add the soffritto, sauté for approximately 5 minutes
Add the mushrooms to the food processor and pulse until the mushrooms to pea-sized pieces
Clear a spot in the bottom of the pot and add the tomato paste, fry for one minute to cook out the raw taste, mix into the soffritto
Add the mushrooms, stir to combine, cover and let steam for 5 minutes. Remove the cover and continue to cook until most of the moisture evaporates 10-15 minutes
Crush the tomatoes by hand directly into the mushroom mixture, stir to combine
Bring the mixture to a boil then reduce heat to low and cover with the lid slightly ajar, simmer for 30 minutes.