Use a potatoe masher or an immersion blender to pulse the whole tomatoes to near liquid and then set to the side.
Finely dice up an onion and add it and the 1 tsp of oil to a sauce pan and cook for approx 2-5 minutes over med high heat, sweating the onion until soft.
Add all the spices to the onion and cook for 1 minute.
Then add all other ingredients, stir well and simmer on medium heat for about 15 minutes, then turn down to low heat and let it simmer for about an hour. If you use a lid on the pan, due to the sauce bubbling and splattering, leave the lid a little askew so condensation so steam can escape.