The soup and sandwich combo of your dreams! The flavors in our Mushroom Grilled Cheese and French Onion Soup make a magical combination. Your taste buds will SWOON! Enjoy this soup and sandwich pairing for a comforting lunch meal, weekday supper, or even a casual Sunday Supper with the family gathered around the table.
Soup and grilled cheese is one of my favorite comfort food combinations that can be customized to easily please the whole family. Today I’m sharing a recipe for French Onion Soup with Mushroom Grilled Cheese because there’s nothing better than cheese on top of cheese! I chose to use Fontina cheese for both the soup and the grilled cheese. But, as I said, you can customize to your taste easily by changing up the type of cheese to use. And if the kids don’t like mushroom, then hey more for you.
Mushroom Grilled Cheese and French Onion Soup Recipe Tips
- I tried making this soup with sweet onion and found that it is too sweet for my taste. Regular yellow onions (brown onions) works fine for me. However, you could use a mixture of sweet onion and yellow (brown onions).
- You have the option to deglaze with some white wine or red wine before adding the rest of the beef broth and let the soup simmer. For me, the wine was too strong so I omit the second time I made this.
- If you want a lighter flavor broth, you could use half beef broth and half chicken or vegetable broth.
- If you really like mushroom and like to layer it on thick, I would double the amount of mushroom called for in the recipe. This is only enough to spread it out in one thin layer when making the mushroom grilled cheese.
- Try making this Instant Pot French Bread to use.
- I couldn’t find sliced Fontina so I bought two 8 oz blocks to use for the soup and the sandwiches. However, you can substitute sliced Swiss cheese for a similar flavor. Or change it up completely with whatever cheese you prefer for your grilled cheese.
I was eating leftover French Onion Soup for days, not that I mind it. But if your family consists of just yourself and your significant other, I would highly recommend cutting the french onion soup recipe down in half. Other than that, enjoy!
Try these easy mushroom recipes!
If you love mushroom recipes, you’ll want to try these:
- Chicken Breast and Mushroom Recipe
- Baked Portobello Mushrooms
- Air Fryer Mushrooms
- Chicken and Mushroom Pie
- Mushroom Swiss Burger
- Button Mushrooms Recipe
- Mushroom Risotto Recipe
- Hungarian Mushroom Soup
- Sauteed Mushrooms and Onions
- Mushroom Grilled Cheese and French Onion Soup
- Mushroom Spinach Pasta
- Vegetarian Stuffed Mushroom Recipe
- Instant Pot Risotto
- Creamy Mushroom Pasta
Our grilled cheese recipes:
- Our Best Grilled Cheese and Soup Pairings
- Pesto Grilled Cheese and Italian Vegetable Soup
- Grilled Cheese and Tomato Soup
French Onion Soup with Mushroom Grilled Cheese
- 2 loaf bread artisan
- 1 pound Fontina cheese
For the soup
- 4 large yellow onions about 3 pounds
- 1/4 cup olive oil
- 4 sprigs thyme
- 2 bay leaves
- 8 cups beef broth
- 1/2 teaspoon black pepper to taste
- 2 teaspoon kosher salt to taste
For the grilled cheese
- 8 ounce button mushroom sliced
- 1 tablespoon olive oil
- 1 sprig thyme
- Salt and pepper to taste
- 4 teaspoons salted butter softened
TO MAKE THE FRENCH ONION SOUP:
- Remove the onion ends, slice in half length wise, and cut into 1/4” thick slices.
- Add olive oil to a large pot and heat over high heat.
- Add onion, thyme and bay leaves and sauté on high heat until onion is translucent and soften, about 5 minutes.
- Season with a few pinches of salt.
- Reduce heat to medium high and continue to cook the onion until soft and caramelized, stirring frequently.
- As the onion gets closer to being caramelized, the bottom of the pan may start to burn, add a little bit of the beef broth to deglaze it as the onion continues to cook.
- When the onion is a deep golden caramel color, about 25 minutes, add the rest of the beef broth to the pot.
- Bring to a boil and simmer for another 10 minutes, season with salt and pepper to taste.
- Shred or grate the cheese, slice to bread into 1/4” - 1/2” round slices that will fit the mouth of a ramekin or oven safe soup crock.
- Remove thyme and bay leaves from the soup, and divide into your container of choice. I used ramekins (see photo above)
- When ready to eat, place a slice of bread on top of your soup and top generously with grated Fontina cheese.
- Broil for 4 minutes until cheese is melted and golden. (See photo above)
- Remove from oven and serve immediately.
TO MAKE THE GRILLED CHEESE:
- Slice the block of cheese into thin slices or use sliced deli cheese.
- Remove thyme leaves from the sprig.
- Heat oil in a skillet over medium high heat.
- Add mushroom and thyme to the skillet and cook until mushroom is softened but not mushy.
- Season with salt and pepper to taste and remove from heat.
- Slice the loaf of bread into 3/8” - 1/2” thick slices.
- Spread 1/2 teaspoon of butter on one side of a slice of bread.
- Place the butter side down on the cutting board and place sliced cheese on top to cover the slice of bread.
- Spread a quarter of the cook mushroom on top of the cheese.
- Add more cheese on top of the mushroom.
- Spread 1/2 teaspoon of butter on one side of a second slice of bread and placed the unbuttered side on top of the loaded slice.
- Place a skillet over medium heat, and use a spatula to transfer the prepared sandwich to the hot skillet.
- Fry until the bottom of the sandwich is golden brown.
- Carefully flip the sandwich and cook the other side until golden brown and the cheese melted.
- Remove from heat and repeat with the rest of the ingredients.