Preheat oven to 400F. Line baking sheet with parchment. Add tomatoes, red onion, garlic, oregano and balsamic to sheet and roast 35 minutes, stirring a couple times. Add veg puree and process until smooth.
Saute mushrooms in a bit of olive oil. When almost cooked add spinach, cover pan and wilt. Add blender contents, tomato paste, salt, pepper, chili flakes, bring to boil and simmer for 5 minutes.
Use over Meaty Cabbage Rolls or Spaghetti Squash.
Use only if you are NOT avoiding nightshade veggies – should be avoided if experiencing a lot of inflammation.
Freeze in 2-cup portions.