Heat the oil in a medium pot before adding the onion and peppers
Simmer them for 5 minutes to soften
Add garlic and stir regularly for 1 minute, or until the air smells garlicky
Add chopped tomatoes, cloves, ground mustard, chili powder, Worcestershire sauce, tomato paste, brown sugar, cider vinegar, allspice, black pepper, and salt to taste
Stir well
Let it boil, then reduce the heat and simmer for 45 minutes or an hour to blend the flavors
Mix the mixture with a stick blender or in batches in a food processor or blender until smooth
Strain ketchup through a fine-mesh sieve for a smooth, elegant texture
Remove remaining solids
Keep sealed containers in the fridge and use as needed
