CLASSIC BEARNAISE AND PALOISE SAUCES

Steps:

• Put the cut-up butter in a 1-cup glass measure with a pouring spout, and microwave until completely melted and clear but not bubbling (or heat in a warm oven, 190 degrees F., about 25 minutes). Skim off any foam from the top, and cool until lukewarm but still liquid.
• Combine the liquids and seasonings (except the cayenne and fresh herbs) in a 3-cup, heavy-bottomed, non-reactive saucepan, and simmer over medium heat until the liquid reduces to 1 tablespoon (no farther). Strain the liquid into a cup, pressing hard to squeeze all the juices out of the shallots, then return it to the saucepan.
• Whisk in the yolk, and place over medium-low heat. Stir in 1/4 of the clarified butter, and continue whisking across the bottom and around the sides of the pan until the yolk-and-butter mixture thickens to a sour cream consistency. If the yolk is overcooked, it will start to scramble; if undercooked (as in "blender Bearnaise" recipes), it will taste raw.
• Dunk the pan briefly in cold water; then very slowly dribble in the rest of the butter off heat, whisking constantly, without including the milky liquid at the bottom. When all the butter is absorbed, the sauce should be the consistency of a medium-thick mayonnaise.
• Add the cayenne pepper, taste for seasoning, and stir in the herbs. To keep the sauce from congealing, set it in a pan of hot tap water, but the sooner it is served, the better.
• For Paloise sauce, omit the tarragon, and finish with 1/2 tablespoon finely shredded mint; do not add mint to the vinegar reduction (the cooking distorts its flavor).
• If the sauce overheats or the butter is added too fast, the oily fat can separate out. If that happens, during or after cooking, it is easy to fix: Put a teaspoon of water in a small bowl, add a spoonful of the separating sauce, and whisk them together until creamy; then gradually add the rest of the sauce, spoonful by spoonful, until the whole thing is reconstituted.