Mash garlic and salt using a large mortar and pestle. Add anchovies, zest, capers, mustard, and pepper; mash to form a paste. Stir in lemon juice. Add oil in a slow, steady stream, working pestle until emulsified; work in cheese. (Or, puree all ingredients except oil and cheese in a blender. Add oil in a slow steady stream, blending until emulsified. Transfer to a bowl; stir in cheese.) Dressing can be refrigerated in an airtight container up to 3 days. Serve at room temperature.