Cheesesteak Style Sloppy Joes (Easy 30-Minute Dinner)

Ingredients

• 1 tablespoon olive oil
• 1 lb (450 g) 85/15 ground beef
• 1 medium yellow onion, finely diced
• 1 green bell pepper, finely diced
• 4 oz (115 g) cremini mushrooms, finely chopped
• 2 cloves garlic, minced
• 1 teaspoon kosher salt, plus more to taste
• 1/2 teaspoon black pepper
• 1 tablespoon Worcestershire sauce
• 1 tablespoon ketchup
• 3/4 cup (180 ml) low-sodium beef broth
• 1 tablespoon cornstarch mixed with 2 tablespoons cold water
• 6 slices provolone cheese
• 4 potato hamburger buns or brioche buns
• 1 tablespoon unsalted butter, softened
• Pickled banana peppers, optional