Ingredients

• 3 tablespoons Dijon mustard
• 1 teaspoon white-wine vinegar
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 6 (5-oz) skinless boneless chicken breast halves
• 1 1/2 English muffins (not sandwich-size)
• 3/4 cup finely grated Parmigiano-Reggiano (1 1/2 oz)
• 1 tablespoon unsalted butter, melted
• Special equipment: parchment paper

Instructions

1. Preheat oven to 450°F and line a baking sheet with parchment.
2. Whisk together mustard, vinegar, salt, and 1/4 teaspoon pepper in a large bowl and add chicken breasts, tossing to coat well.
3. Pulse English muffins in a food processor until finely ground. Add cheese, butter, and remaining 1/4 teaspoon pepper and pulse until combined well. Transfer to a shallow soup plate or pie plate.
4. Dredge chicken, 1 piece at a time, in crumbs, coating completely and pressing gently to help crumbs adhere, then transfer to baking sheet. Bake in middle of oven until golden brown and cooked through, 15 to 20 minutes.