A comforting yet classy sandwich featuring gooey Swiss cheese, sautéed mushrooms, and crispy sourdough bread, perfect for lunch or dinner.
For extra flavor, add caramelized onions or sprinkle crushed red pepper flakes. Use Gruyère or Havarti cheese as alternatives to Swiss. Keep the heat medium to avoid burning the bread.
Keywords: Swiss cheese, mushroom sandwich, grilled cheese, sourdough sandwich, quick lunch, vegetarian sandwich