Béarnaise Sauce

• 1 tablespoon plus 1 cup (2 sticks) unsalted butter, cut into 1/2" cubes
• 3 tablespoons minced shallots
• Kosher salt and freshly ground black pepper
• 2 tablespoons Champagne vinegar or white wine vinegar
• 2 large egg yolks
• 1 tablespoon (or more) fresh lemon juice
• 1 tablespoon finely chopped fresh tarragon

1. Melt 1 tablespoon butter in a small saucepan over medium heat. Add shallots and a pinch of salt and pepper; stir to coat. Stir in vinegar, reduce heat to medium-low, and cook until vinegar is evaporated, 3-4 minutes. Reduce heat to low and continue cooking shallots, stirring frequently, until tender and translucent, about 5 minutes longer. Transfer shallot reduction to a small bowl and let cool completely.
2. Meanwhile, fill a blender with hot water to warm it; set aside. Melt remaining 1 cup butter in a small saucepan over medium heat until butter is foamy. Transfer butter to a measuring cup.
3. Drain blender and dry well. Combine egg yolks, lemon juice, and 1 tablespoon water in warm, dry blender. Puree mixture until smooth. Remove lid insert. With blender running, slowly pour in hot butter in a thin stream of droplets, discarding milk solids at bottom of measuring cup. Continue blending until a smooth, creamy sauce forms, 2-3 minutes. Pour sauce into a medium bowl. Stir in shallot reduction and tarragon and season to taste with salt, pepper, and more lemon juice, if desired. DO AHEAD:

unsalted butter, shallots, kosher salt, vinegar, egg yolks, lemon juice, tarragon

Taken from www.epicurious.com/recipes/food/views/bearnaise-sauce-395049 (may not work)