Easy Hollandaise Sauce
["1 egg yolk, slightly beaten", "1 to 1 1/2 Tbsp. lemon juice", "1/2 stick cold butter (1/4 c.) in saucepan"]
["Cook over low heat, stirring constantly, until butter melts and sauce is slightly thick.", "Season to taste with salt.", "Makes 1/2 cup sauce."]
["egg yolk", "lemon juice", "cold butter"]