Ingredients

• ¹⁄₄ cup aged red wine vinegar
• 1 tbsp. Dijon mustard
• ¹⁄₂ cup cooking stock from Tête de Veau or beef stock
• Kosher salt and freshly ground black pepper
• Pinch of cayenne
• 1 cup sunflower oil
• 1 cup minced chives
• ³⁄₄ cup finely chopped parsley
• ¹⁄₂ cup minced chervil
• ¹⁄₂ cup minced tarragon
• ¹⁄₄ cup capers, rinsed and minced
• 2 small shallots, minced
• 1 hard boiled egg, finely chopped
• 1 garlic clove

Instructions

1. In a small saucepan, reduce the cooking liquid or stock by half over high heat, about 5 minutes.
2. Cool, then transfer to a blender along with the vinegar, mustard, salt, pepper, and cayenne. With the motor running, slowly drizzle in the oil until emulsified.
3. Transfer to a bowl along with the chives, parsley, chervil, tarragon, capers, shallots, and egg. Using a microplane, grate the garlic into the bowl, then stir everything to combine.

Notes

Source: Saveur.com