Gourmet Cheesy Mushroom and Garlic Toasts | Elegant Appetizer

Ingredients

• 400 grams sliced cremini mushrooms
• 2 tablespoons salted butter
• 1 tablespoon olive oil
• 1 tablespoon Worcestershire sauce
• 1/4 teaspoon salt
• 1/4 teaspoon ground black pepper
• 1/2 cup mayonnaise
• 1/4 cup sour cream
• 2 tablespoons melted butter
• 2 cloves garlic, finely minced
• 1 tablespoon dried onion flakes
• 1/2 cup grated parmesan cheese
• 1/2 cup grated havarti cheese
• 1/2 cup grated swiss cheese
• 1/2 cup mozzarella cheese
• 1/4 cup green onions, thinly sliced
• 4 slices sourdough bread