Sunny's Patty Melt Muffaletta

Mushroom Topping:

• 1 tablespoon butter
• 1 tablespoon olive oil
• 8 fresh sprigs thyme, stripped and chopped
• 1/2 onion, finely chopped
• 1/2 serrano chile pepper, seeded and finely chopped
• Pinch salt
• Grind or two freshly ground black pepper
• 8 button mushrooms, sliced

Patty:

• 1 teaspoon Worcestershire sauce
• 1/2 teaspoon salt
• A few grinds freshly ground black pepper
• 1 clove garlic, grated on a rasp
• 8 ounces ground chuck
• Two 7-to-8-inch-round flatbreads, such as Aladdin or Metsuyan
• 3 slices American cheese
• 4 strips bacon, cooked and chopped
• 4 ounces smoked mozzarella, sliced or torn into bits
• Ketchup, for serving