Philly Cheese Steak Sloppy Joes (Easy Skillet Dinner)

Ingredients

• 4 hamburger buns or brioche buns
• 1 tablespoon (14 g) unsalted butter, softened
• 1 tablespoon (15 ml) olive oil
• 1 lb (450 g) ground beef, 85/15 or 90/10
• 1 medium yellow onion, diced
• 1 medium green bell pepper, diced
• 2 cloves garlic, minced
• 1 tablespoon (15 ml) Worcestershire sauce
• 2 tablespoons (30 g) ketchup
• 1 teaspoon Dijon mustard
• 3/4 cup (180 ml) low-sodium beef broth
• 1 tablespoon (8 g) cornstarch
• 1/2 teaspoon kosher salt, plus more to taste
• 1/2 teaspoon black pepper
• 6 slices provolone cheese, about 4 oz (115 g)
• Pickled banana peppers, optional for serving