A simple sauce that is often served with bollito misto, the mixed boiled meat dish of central Italy, this is a great homemade replacement for ketchup. Nice with grilled meats.
Combine the first 5 ingredients in a bowl and let sit for an hour.
Add the tomato paste and mustard, then taste and add more salt, pepper, and vinegar if necessary. Serve immediately or cover and refrigerate; this will keep it’s flavor for several days.