01 - Warm 2 tablespoons butter and 1 tablespoon olive oil in a large skillet over medium heat.
02 - Add sliced mushrooms and cook for 6 to 8 minutes, stirring occasionally, until softened and golden brown.
03 - Incorporate minced garlic, thyme, salt, and black pepper; cook for 2 minutes until fragrant.
04 - Stir in chopped parsley and optional lemon juice; adjust seasoning as needed.
05 - Toast bread slices until crisp and golden; while hot, spread with 1 tablespoon unsalted butter.
06 - Spoon garlic mushroom mixture evenly over toasted bread slices.
07 - Top with extra parsley and, if desired, grated Parmesan cheese; serve immediately.