• 3 teaspoons vegetable oil, divided
  • 4 slices thick of bread (Italian French, sourdough, or your favorite)
  • 1 tablespoon unsalted butter, room temperature
  • half huge onion, sliced into half circles
  • 1 teaspoon kosher salt, divided
  • five ounces infant portabella mushrooms, sliced
  • half of cup freshly shredded Swiss cheese, divided


  1. In a skillet over medium-excessive warmness, add 2 tsp. Of vegetable oil. When oil is hot, upload the onions and 1/2 tsp. Of salt and cook dinner till dark brown in coloration and softened. Halfway through, you’ll want to show down the heat to medium heat. Caramelizing onions will take about 20-half-hour. If you note that your pan is getting slightly dry, including a tablespoon of water will help the caramelizing alongside. The water ought to sizzle and fast evaporate. You’re not looking to have the water live within the backside of the skillet at the same time as cooking the onions.
  2. When the onions are caramelized, do away with from skillet and vicinity in a bowl. Add the last 1 tsp. Of vegetable oil to the skillet and add the mushrooms and ultimate half of tsp. Of salt. Cook the mushrooms until softened, about 5 mins. Remove from skillet; keeping the liquid that has accumulated within the skillet.
  3. Preheat broiler in oven.
  4. Take the room temperature butter and butter both sides of bread. Place bread directly to a baking sheet and area below broiler for approximately 1 minute every side. Carefully take away bread from baking sheet and on a fair floor, start to gather your sandwich.
  5. Place caramelized onions on one slice of bread, then the mushrooms on top, then 1/four cup of shredded Swiss cheese. Gently area on baking sheet. Repeat with some other slice of bread. Place baking sheet into the oven and broil for 1-2 minutes till cheese is melted and bubbly.
  6. Remove from oven and location the last  slices of bread on pinnacle of each and gently press down.
  7. Slice sandwiches in 1/2 and serve!