Just saute minced onion and garlic for 5 minutes, then add canned whole tomatoes, tomato sauce, tomato paste, Italian seasoning, red pepper flakes, salt and pepper. (bitesofflavor.com)
If you're really having trouble sourcing tomatoes, buy canned whole tomatoes (reserve the juice for the blender). (soupaddict.com)
Pour canned whole tomatoes and their juices into a large bowl. (aggieskitchen.com)