Prep your ingredients. Slice mushrooms evenly so they cook at the same rate. Mince garlic and chop the shallot and parsley. Preheat your skillet over medium-high heat.

Brush each slice of bread with a little olive oil or butter and toast in a skillet or oven until golden. Set aside on a plate.

Add 1 tablespoon of olive oil and 1 tablespoon butter to the hot skillet. Once the butter foams, add the mushrooms in a single layer. Let them sit undisturbed for 2–3 minutes to develop a golden sear.

Stir and cook for another 2 minutes until the mushrooms release their juices and the shallot softens. Lower the heat slightly to avoid burning the garlic.

Stir in thyme, salt, and pepper. Add balsamic vinegar or lemon juice if using, and sauté for another minute to let flavors marry. Toss in the parsley off the heat.

Pile the garlic mushrooms onto the toasted slices. Sprinkle with grated Parmesan or crumbled goat cheese if you like. Finish with a final drizzle of olive oil or a pinch more black pepper.

Serve immediately. These are best fresh when the toast is still crisp and the mushrooms are warm.