Add all the ingredients to your high speed blender and process until completely reduced to a fine, liquid puree.
Transfer that puree to a medium saucepan and bring to a boil. Lower the heat, cover partly and simmer for 25 to 30 minutes, stirring from time to time, until the sauce thickens and gets darker in color.
Kill the heat and let the tomato sauce come down to room temperature. Transfer to airtight glass (or other non-reactive) containers and refrigerate until completely chilled.
The ketchup gets even better after sitting in the fridge for a few days and it will keep for about 3 to 4 weeks in the refrigerator. It also freezes very well and will keep for several months in the freezer.