1 anchovy, 1 garlic clove [a wee one], 1/2 fresh lemon, 1 tsp. Dijon mustard, 1/4 cup olive oil [or a bit less], salt, pepper
Mush up the garlic, anchovy and a pinch of salt with a mortar + pestle until it turns to a paste. Add juice from 1/2 lemon and stir, followed by the mustard and olive oil. Whisk until smooth-ish, and season to taste with pepper [or cayenne, for kick]. Best served over a bitter and bold greens mix [arugula and friends].
Recipe found via Food 52