Brush rustic bread with olive oil, then toast under the broiler or in toaster until golden and crisp, about 2–3 minutes per side.

Melt butter over medium heat until foamy, then stir in minced garlic and thyme, cooking briefly until fragrant, about 1 minute.

Add sliced mushrooms, tossing occasionally until they release their juices and turn golden brown, about 5–7 minutes for earthy perfection.

Season with salt and pepper, tasting and adjusting for balance, then gently remove the pan from heat to prevent overcooking.

Spoon the garlic butter mushroom topping over warm, crisp toast, then garnish with parsley and a sprinkle of Parmesan for an elegant finish.