Ingredients
Equipment
Method
Preparation Steps
- Thinly slice the yellow onions. In a skillet, heat olive oil and butter over low heat. Add onions and cook for 30-45 minutes until golden brown.
- Sprinkle in brown sugar and balsamic vinegar once onions are caramelized. Cook for an additional 2-3 minutes and remove from heat.
- In the same skillet, add more olive oil and sliced mushrooms. Sauté for 8-10 minutes until golden brown. Add minced garlic and thyme, cooking for an additional minute.
- Pour in dry white wine and scrape the bottom of the pan, simmer for 2-3 minutes until nearly evaporated. Remove from heat.
- Butter one side of each sourdough slice. On the unbuttered side, layer Swiss cheese, caramelized onions, and sautéed mushrooms. Optionally spread mustard on two unbuttered sides.
- Heat the skillet and place sandwiches in. Cook for 3-5 minutes on each side until golden brown and cheese is melted.
- Remove from skillet, let rest, cut in half, and serve immediately.
Nutrition
Notes
Perfect caramelization requires low heat. Season mushrooms to taste. Use fresh sourdough for the best texture. Cover skillet while grilling for even cheese melting. Don't overcrowd mushrooms when sautéing.
