From The Way to Cook by Julia Child. I spread this all over a butterflied leg of lamb and refrigerate overnight before grilling it.
2 large cloves of garlic
1/2 tsp. salt
2 Tbs Dijon-style prepared mustard
1 Tbs soy sauce
1-1/2 tsp. fragrant ground rosemary, thyme, or oregano
2 Tbs freshly squeezed lemon juice
1/4 cup olive or peanut oil
Purée the garlic into a small bowl (I put it through a press) and mash to a paste with the salt. Whisk in the mustard, soy, herbs, lemon juice, and then the oil, to make a mayonnaise-like cream.