Onion Mustard Hamburger Buns

Ingredients

• 5 1/2 to 6 cups bread flour, divided
• 2 (0.25oz each) packages (14g) or 4 1/2 teaspoons Red Star Active Dry Yeast
• 2 tablespoons granulated sugar
• 1 tablespoon fine salt
• 1/4 teaspoon white pepper
• 1 cup milk
• 1 cup water
• 2 tablespoons vegetable oil
• 1 tablespoon prepared mustard
• 2 tablespoons instant minced onion
• 1 large egg
• 1/4 cup water
• 1 large egg (slightly beaten)