Béarnaise Sauce

Makes 1-1/4 cups.
1/2 cup white wine vinegar
2 sprigs fresh tarragon
1 shallot, minced, sliced thin
3 large egg yolks
1-1/2 teaspoons lemon juice
Salt [Sea salt or Kosher]
Pinch Cayenne Pepper
Extra seasoning per taste
16 tablespoons unsalted butter, melted and hot
Hot water
1. Bring vinegar, tarragon sprigs, and shallot to simmer in small skillet over medium heat. Cook until vinegar is reduced to about 2 tablespoons, 5 to 7 minutes. Remove from heat. Use fork and discard shallot slices and tarragon sprigs.
2. Process egg yolks, lemon juice, 1/4 teaspoon salt, cayenne, and vinegar mixture in blender until frothy, about 10 seconds. With blender running, slowly drizzle in hot butter until emulsified, about 30 seconds. 
3.  Stir in minced tarragon. Adjust consistency with hot water as needed, 1 teaspoon at a time, until sause slowly drips from spoon. Extra seasoning per taste.