25 g dry English-style mustard (more if you want more punch, Coleman's Dry Mustard in the U.S. is not gluten-free)
1 tablespoon fresh lemon juice
3 medium eggs (2 separated, 1 whole)
250 ml light vegetable oil
250 ml olive oil
2 tablespoons white wine vinegar
Sea salt, to taste
Fresh ground black pepper, to taste
Making the mayonnaise in a Mixing Bowl with a Whisk: Start by mixing together the mustard and lemon juice in a bowl; add 2 egg yolks and mix well; mix the 2 lots of oil together in a jug and start to add them a drop at a time to the egg mixture, while continuing to whisk; finally, add the white wine vinegar and then the remaining whole egg; and season to taste.
Making the mayonnaise in a food processor: Start by processing together the mustard and lemon juice, add the 2 egg yolks and process again so that all the ingredients are mixed well together; mix the 2 lots of oil together in a jug and start to add them in a gentle stream while the processor is running; finally, add the white wine vinegar and then the remaining whole egg; and season to taste, and process for a few moments to ensure that all the ingredients are well-combined.