Combine the egg yolks, mustard, garlic clove, cayenne and lemon juice in a food processor. (Or use a stick blender)
Start to process, and as the machine runs, very slowly add the oil in a thin stream through the top spout. The mayonnaise will come together and thicken all of a sudden.
If the mixture is too thick, add a little warm water to thin it.
Add salt and pepper to taste.
The mayonnaise will keep for about 1 week in the refrigerator.
Enjoy with mustard greens (above), or any dish that calls for mayonnaise.
Rinse and dry the mustard greens.
Slice away the stems, fold over the leaves and cut them into bite-size pieces.
In a large bowl, toss the mustard greens and the minced pepper (if using) with a little of the mayonnaise, adding a little at a time and tasting as you go. The leaves should be lightly coated but not soggy with the mayonnaise.