Place everything except the oil, salt and lemon into a food blender and begin to belne. Drizzle in the oil in a steady slow stream a little at a time. Stop the machine every now and again to scrape down the sides with a spatula.
Continue until all the oil is incorporated and you should have a nice, mayo like dressing with some punch and flavour. Correct the seasoning and set aside for use. Keeps quite happily in the fridge for up to a week.