Are you looking to change up your normal lunchtime menu? This caramelized onion, mushroom, and Swiss melt will definitely break up the monotony. Its open-faced appearance not only looks appealing, but also has less calories and carbs by having only one slice of bread. Plus, the caramelized sweet onions have a superb flavor thanks to the French technique of deglazing the pan. 👨🍳👩🍳
Are you a cheese lover? Well, you’ll delight in taking a bite and seeing the ooey gooey strings of the melted Swiss cheese stretch to new lengths. 😄 Can’t decide between mayo or Dijon? This recipe combines both to give this Swiss melt just enough tang.
The finishing touch is a generous helping of fresh mushrooms that are sauteed in butter. Serve this on a slice of our super easy homemade Italian bread, and you’ll gladly trade your trusty PBJ for this fresh burst of flavor.Print
Caramelized onion, mushroom, and Swiss melt is an easy recipe for a low carb, open faced lunch or dinner sandwich packed with gooey cheese, pan-fried mushrooms, and beautiful caramelized onions. It’s all made in only 45 minutes!
- 3 tablespoons butter
- 1 pound mushrooms, sliced
- 2 tablespoons butter
- 1 sweet onion, sliced
- 2 teaspoons fresh rosemary, chopped
- 1/4 cup white wine
- sprinkle salt and pepper
- 1/2 pound Swiss cheese, thinly sliced
- 6 large slices Italian white bread
- 6 tablespoons mayo
- 1 tablespoon Dijon mustard
- sprinkle salt and black pepper
Preparing the Veggies and Cheese
- Wash and slice the mushrooms. In a large saucepan, melt 3 tablespoons of butter, then add the sliced mushrooms. Cook the mushrooms for about 15 minutes, stirring occasionally.
- While the mushrooms cook, slice the sweet onion and break apart into rings. Add 2 more tablespoons of butter to the large saucepan and stir in the sliced onions.
- While the onions are cooking with the mushrooms, chop up the fresh rosemary and add it to the pan. Sprinkle the vegetables with salt and pepper to taste. Cook the onions until soft and golden brown, stirring often.
- To deglaze the pan, pour in 1/4 cup white wine. (Refer here if you need additional info about deglazing the pan.) Stir constantly for two minutes. Remove the pan from the heat, and put the vegetables in a bowl.
- Thinly slice half a pound of Swiss cheese and place in a pile on top of piece of paper towel.
Making the Sandwich Spread
- In a small bowl, combine the mayo, Dijon mustard, and a sprinkle of salt and pepper. Stir well to combine.
Assembling the Sandwiches
- Position the oven rack to the second rung from the top. Turn the broiler on high.
- On a large rimmed baking sheet, place six large slices of white Italian bread. Spread each slice with the mayo/Dijon spread.
- Cover each slice of bread with 6 or 7 slices of Swiss cheese. Evenly distribute the onion mushroom mixture on top of each slice. As a finishing touch, freshly grate more Swiss cheese on top.
- Cook under the broiler for 3 to 4 minutes. Watch carefully so they don’t burn.
- Cut each slice in half and serve warm.
- Need to make this ahead of time? Reheat under the broiler on a baking sheet for two minutes before serving since this sandwich is best served warm.