Tongue Sandwich with Tarragon or Parsley Sauce Recipe

Ingredients (16)

• 1 cow or veal tongue, about 1 1/2 pounds
• 2 medium onions, peel on
• Kosher salt and freshly ground black pepper
• 2 tablespoons vegetable or canola oil
• 1 slice rustic bread, crust removed, torn into small pieces (about 1/4 cup)
• 3 1/2 tablespoons red wine vinegar
• 2 tablespoons drained capers, finely chopped
• 4 anchovy fillets, minced
• 2 medium garlic cloves, minced or grated with a microplane grater (about 2 teaspoons)
• 1 tablespoon Dijon mustard
• 1/4 cup olive oil
• 3 tablespoons minced tarragon or parsley leaves, or a mix
• 1 boiled egg, yolk and white separated
• 2 baguettes, or 8 slices of bread
• 1/4 cup prepared horseradish
• Arugula, watercress, or some kind of bitter green