Let’s dive into the creation of this melt, a process that’s as enjoyable as it is simple, much like the many meals crafted in my family’s kitchen over the years.

1. Heat the olive oil and one tablespoon of butter in a large skillet over medium heat.
2. Add the sliced mushrooms and cook, stirring occasionally, until they are golden brown and have released their moisture, about 7-8 minutes.
3. Add the chopped onion, garlic, and thyme to the skillet. Cook until the onion is soft and translucent, about 5 minutes. Season with salt and pepper to taste.
4. Remove the mushroom mixture from the skillet and set aside.
5. Spread mayonnaise on one side of each slice of sourdough bread. This is a little trick my mother taught me for achieving that perfect golden crust.
6. Place two slices of bread, mayonnaise side down, in the skillet. Layer each with two slices of Swiss cheese, the mushroom mixture, and then two more slices of cheese.
7. Top with the remaining slices of bread, mayonnaise side up.
8. Cook the sandwiches over medium heat until the bread is golden brown and the cheese is melted, about 3-4 minutes per side. Use the remaining butter to ensure a beautiful crust.
9. Remove from the skillet, slice, and serve immediately.