Portobello Mushroom Burgers

Bahan-bahan (4 porsi)

• 4 large portobello mushrooms (see note)
• 2 tablespoons olive oil
• 2 teaspoons soy sauce
• 1 teaspoon Worcestershire sauce
• 1 clove garlic (minced)
• salt and black pepper (to taste)
• 3 ounces havarti cheese (sliced)
• 4 hamburger buns (or brioche buns)
• toppings (as desired)