In a blender chop the whole tomatoes with juice and garlic until chunky. In a medium size pot heat oil on medium high heat. Put onion and mushroom in and saute for about 5 minutes.
Place in pot the blended tomatoes, crushed tomatoes, tomato paste, chopped green capsicums, oregano and basil. Bring to boil, then lower to medium low, cover and stir periodically. Cook and reduce about 1 to 2 hours or to your liking.