2 slices good bread, crusts removed and cut into cubes
1 clove garlic
Put the egg yolks, water, lemon juice, mustard, anchovies and black pepper in a blender. Blitz together and then add the oil in a slow steady stream to build up an emulsion (a thick, creamy dressing). Add the parmesan and pulse a couple of times. Set aside. Taste, adding a little vinegar if necessary.
In a frying pan over a medium heat add some olive oil and a knob of butter. When it foams add the cubes of bread and fry on all sides till golden brown and set aside on kitchen paper.
Smash the garlic clove under the heel of your palm and run it around the inside of your serving bowl. Discard the clove and add the lettuce and as much of the dressing as you need to give each leaf a good coating.
Toss together before sprinkling over the croutons and serving.