Roasted Mushroom & Onion Grilled Cheese Sandwich Recipe Elevates Sandwich Night by Melissa Vickers

Roasted Mushroom & Onion Grilled Cheese Sandwich Recipe Elevates Sandwich Night

Even the plainest of grilled cheese sandwiches is warm and satisfying comfort food. They don’t have to be plain, though, with choice of bread, cheese and other add-ins, you can turn this simple hot sandwich into a gourmet meal.

This grilled cheese sandwich recipe starts with roasted mushrooms and onions and ends with cheesy goodness. You can use whatever cheese you like best. I use a fiesta Mexican blend cheese, but gouda, cheddar, provolone, Swiss, Gruyere or muenster would be just as delicious. Mix and match until you get the perfect cheese blend.

Serve this cheesy sandwich for lunch or for dinner with a salad or bowl of soup. The classic tomato soup and grilled cheese combination, just updated a bit!

Cuisine: American
Prep Time: 15 minutes
Cook Time: 30 minutes
Total Time: 45 minutes

Servings: 2


  • 8 ounces of mushrooms, sliced
  • 1 medium onion, sliced (sweet onions are best)
  • 2 tablespoons olive oil
  • 4 tablespoons butter
  • 4 slices bread 
  • 1 cup shredded cheese (I used a fiesta blend)

Here’s how to make it:

  1. Toss sliced mushrooms and onion in olive oil on a baking sheet. Sprinkle with a few pinches of salt and pepper. Bake in a preheated 400-degree F oven for about 20 minutes.
  2. Melt butter in skillet over medium heat. While it’s melting, assemble sandwiches. On one slice of bread, layer shredded cheese, roasted vegetables and then more cheese. (The two layers of cheese help hold the sandwich together.) Lightly press together.
  3. Place one sandwich in the melted butter for one second, then gently flip it over to the other side. Repeat with other sandwich. Cook for about 2 minutes, or until lightly browned. Use a pastry brush to brush more of the melted butter if it seems dry. Gently flip sandwich to the other side and cook for an additional 2 to 3 minutes, or until cheese is melted and sandwich is browned to your liking.

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