Preheat the oven to 400°F (200°C).

Cut the top off the head of garlic to expose the cloves.

Drizzle with 1 teaspoon olive oil, wrap in foil, and roast for 30-40 minutes until soft and golden brown.

Let it cool slightly, then squeeze out the soft, caramelized garlic cloves and mash them into a paste. Set aside.

Heat 1 tablespoon olive oil and 1 tablespoon butter in a large pan over medium heat.

Add the sliced mushrooms, spreading them out evenly. Let them cook without stirring for 2-3 minutes to get a nice sear.

Stir and cook for another 3-4 minutes until golden brown.

Add the salt, black pepper, thyme, and red pepper flakes. Stir well.

Deglaze with white wine or balsamic vinegar (if using), then add Worcestershire sauce for extra depth.

Reduce heat and stir in the roasted garlic paste and heavy cream or sour cream (if using). Cook for 1-2 more minutes. Remove from heat.

Preheat the oven broiler to high.

Place bread slices on a baking sheet and lightly toast them in the oven for 2-3 minutes until just golden.

Spread each slice with a thin layer of roasted garlic paste.

Top with the cooked mushrooms and sprinkle generously with shredded cheese and grated Parmesan.

Place the toasts back under the broiler for 2-4 minutes, until the cheese is melted and bubbly.

Remove from the oven and sprinkle with fresh parsley.

Serve immediately while the cheese is hot and gooey.