Pin It There's something about the smell of mushrooms browning in butter that stops me in my tracks every time. I used to think grilled cheese was just a childhood comfort food, something you threw together without much thought. Then one rainy afternoon, I had a block of Swiss cheese in the fridge, a handful of mushrooms going soft, and a craving for something warm and substantial. What came out of that skillet changed how I thought about sandwiches entirely.
I made this for my sister once when she stopped by unannounced, cold and hungry after a long drive. She stood in the kitchen, skeptical at first, watching me layer mushrooms between cheese. But the moment she bit into that crispy, golden sandwich, she closed her eyes and nodded slowly. She didn't say much, just asked for the recipe before she left. That silence told me everything.
Ingredients
- Cremini or white button mushrooms: Cremini have a deeper, earthier flavor, but button mushrooms work beautifully too. Clean them with a damp cloth instead of soaking them, or they'll soak up water and turn soggy in the pan.
- Shallot: Milder and sweeter than onions, shallots add a delicate layer of flavor that doesn't overpower the mushrooms. If you don't have one, half a small yellow onion works in a pinch.
- Garlic: Just one clove is enough to add warmth without stealing the show. I mince mine finely so it melts into the mushrooms rather than sitting in sharp little chunks.
- Swiss cheese: It melts like a dream and has a nutty, slightly sweet flavor that pairs perfectly with mushrooms. Look for good quality Swiss with visible holes for the best melt and taste.
- Unsalted butter: Softened butter spreads easily on the bread and gives you control over the salt level. I always keep extra on hand because mushrooms love butter.
- Rye bread: The slight tanginess and hearty texture of rye stand up to the rich filling without getting soggy. If you're not a rye fan, sourdough is a solid substitute.
- Olive oil: I use it to start the mushrooms because it can handle higher heat than butter alone, giving you a better sear without burning.
- Fresh thyme: Optional, but those tiny leaves add a fragrant, earthy note that makes the whole kitchen smell like a French bistro.
Instructions
- Start the aromatics:
- Heat the olive oil and a tablespoon of butter in a skillet over medium heat until the butter foams. Add the shallot and let it sizzle gently for about a minute, stirring once or twice, until it softens and smells sweet.
- Cook the mushrooms:
- Toss in the sliced mushrooms and stir them around so they're coated in the butter and oil. Let them cook undisturbed for a couple of minutes to get some color, then stir every minute or so for 5 to 7 minutes total until they're golden brown and all the moisture has cooked off.
- Add garlic and thyme:
- Stir in the minced garlic and thyme leaves, letting them cook for just a minute until fragrant. Season everything with salt and black pepper, then take the skillet off the heat and set the mushrooms aside.
- Build the sandwiches:
- Lay out your four slices of rye bread. Place a slice of Swiss cheese on two of them, spoon the warm mushroom mixture evenly over the cheese, then top each with another slice of Swiss and the remaining bread.
- Butter the outside:
- Spread softened butter generously on the outer sides of each sandwich, making sure to get all the way to the edges. This is what gives you that perfect golden crust.
- Grill to perfection:
- Wipe out the skillet and return it to medium low heat. Place the sandwiches in the pan and cook for 3 to 4 minutes on each side, pressing gently with a spatula, until the bread is crispy and golden and the cheese has melted into gooey perfection.
- Serve:
- Slice each sandwich in half and serve immediately while the cheese is still stretchy and warm.
Pin It 
The first time I nailed this sandwich, I ate it standing at the counter, unable to wait long enough to sit down. The cheese stretched between the two halves, the mushrooms were savory and rich, and the rye bread had this perfect crunch that gave way to soft, buttery layers. It's become my go to whenever I want something that feels like a hug but tastes like I actually tried.
Choosing Your Mushrooms
Cremini mushrooms are my favorite for this recipe because they have more flavor than white buttons and hold up well to sautéing. If you can find baby bellas, grab those, they're just young portobellos with a meaty texture and earthy taste. Shiitakes work beautifully too, though you'll want to remove the tough stems first. Whatever you choose, make sure they're firm and dry, not slimy or bruised.
Bread and Cheese Swaps
Rye is traditional here, but sourdough or a hearty whole grain bread will give you a different kind of satisfying bite. As for cheese, Gruyère is a luxurious swap with a nuttier, more complex flavor, and Emmental melts just as smoothly as Swiss. I've even used fontina when I wanted something creamier and milder. Just avoid pre shredded cheese, it doesn't melt the same way because of the anti caking agents.
Serving Suggestions
This sandwich shines next to a bowl of tomato soup, the acidity cutting through the richness perfectly. A simple green salad with a tangy vinaigrette works too, especially if you're trying to balance out the indulgence. On cooler evenings, I'll pour a glass of Sauvignon Blanc or a light Pinot Noir, both of which complement the earthy mushrooms without overpowering the delicate Swiss.
- Add a smear of Dijon mustard inside for a sharp, tangy kick.
- Serve with pickles or cornichons on the side for contrast.
- Pair with a cup of hot cider or black tea if you're skipping the wine.
Pin It This sandwich has earned a permanent spot in my weekly rotation, and I hope it does the same for you. There's nothing quite like the combination of crispy bread, melted cheese, and savory mushrooms to remind you that simple food, done right, is often the most satisfying.
Recipe Questions & Answers
- → Can I use different types of mushrooms?
Yes, cremini and white button mushrooms work best for this sandwich, but you can also use oyster, shiitake, or a combination. Just ensure they're sliced evenly so they cook through.
- → What if I don't have rye bread?
Rye bread adds an earthy flavor, but sourdough, whole wheat, or white bread work well too. Choose a bread sturdy enough to hold the fillings without falling apart.
- → How do I prevent the bread from burning while the cheese melts?
Use medium-low heat and cook 3-4 minutes per side. This allows the bread to crisp without burning while the cheese melts evenly. A spatula helps distribute heat by pressing gently.
- → Can I make this ahead of time?
You can prepare the mushroom filling up to 24 hours ahead and store it in the refrigerator. Assemble and cook the sandwiches fresh just before serving for the best texture.
- → What are good side pairings?
Tomato soup is classic, but consider pairing with a simple green salad, pickle spears, or potato chips. A crisp white wine like Sauvignon Blanc complements the earthy mushrooms and creamy cheese nicely.