cheesy mushroom onion sandwich

Cheesy Mushroom Onion Sandwich

Sandwiches are easy to make and filling for the stomach at the same time. This Cheesy Mushroom Onion Sandwich recipe is an apt dish that you can enjoy for breakfast, evening snack, or brunch. Made with caramelised mushrooms and onions, seasoned just right, topped with lots of cheese stuffed in bread slices, and grilled to perfection, it is an easy recipe and won’t even take up too much of your valuable time. This tempting sandwich recipe can be relished by people of all age groups and is quite sumptuous. Served with a dip or some coleslaw, this vegetarian recipe has the ability to become one of your favourites.

cheesy mushroom onion sandwich

Reasons to Make This Cheesy Mushroom Onion Sandwich

  • Effortless and foolproof
  • Takes less than 20 minutes to come together
  • Packed with flavours
  • Cheese! (yes, that counts as a whole reason)
  • Extremely adaptable and can be improvised according to one’s preferences.
  • Adults love it. Kids Love it.
  • Great for brunch, breakfast, picnic, packed lunch.
  • Filling and satiating.

Ingredients in This Cheesy Mushroom Onion Sandwich

Let’s take a look at the key ingredients:


Mushroom is one of the star ingredients of this recipe. If you’re not a big fan of mushrooms, this is probably not for you because the piquant flavour of mushrooms dominates this recipe. The earthy tones of mushrooms also complement the richness of the cheese and the sweetness of the onions.

cheesy mushroom onion sandwich

You can use any kind of mushroom or a combination of the same. I’ve used button mushrooms for this recipe which is very easily and abundantly available around where I live. The big chunks of mushrooms provide a meaty bite to your cheesy sandwich. One word of caution while cooking the mushrooms – do not salt them right in the beginning and do not touch them too much while they cook. These two tips ensure that the mushrooms turn crispy and not soggy. 


Cheese makes the world a better place. It can be eaten as is, paired with wine, melted into a dip, or in the case of this recipe, grated onto a layer of mushroom-onion stuffing melts while grilling the sandwich and elevates this dish by folds. Also, there’s no such thing as too much cheese so go crazy with the cheese or skip it if you like. Completely your call!


Make sure you use any type of fresh good quality bread – large white bread, wholewheat multigrain bread, or panini bread like I have used to ensure that you get the best sandwich possible.


The onions lend a delicious sweetness and crunch to every bite of the mushrooms. Mushrooms and onions are a great combination and they work like magic in this sandwich. The onions are sliced thinly and cooked on medium to high flame till they turn golden brown, yet remain crunchy.

cheesy mushroom onion sandwich

Preparation time – 20 minutes

Cook time – 30 minutes

Serves – 3


  • 200 g button mushrooms, sliced
  • 2 bread slices/panini bread
  • 2 medium-sized onions, thinly sliced
  • 2 tbsp oil
  • 2 tbsp butter
  • 1 tbsp finely chopped garlic
  • Salt to taste
  • 1/2 tsp black pepper powder
  • 6-8 Italian basil leaves, chopped
  • 1 cup grated cheese (per sandwich)
  • Butter for toasting the sandwich 


For the stuffing:

  1. Finely slice your onions and set them aside.
  2. Similarly, finely slice your mushrooms and set them aside.
  3. In a pan, heat some oil.
  4. Add the butter to the oil. Adding butter and oil together prevents the butter from burning.
  5. To the melting butter, add the finely chopped garlic.
  6. Sweat the garlic for a few seconds, do not brown it. 
  7. Now, add in the sliced onion and saute with the garlic, stirring occasionally.
  8. Caramelise the onions well till it’s golden brown.
  9. Add in the sliced button mushrooms.
  10. Give it a light stir and top it with some butter or oil if needed. 
  11. Leave the mushrooms untouched for a few minutes and let them cook. This will ensure that the mushrooms turn crispy and not soggy. 
  12. Caramelise the mushrooms with the onions as well, stirring gently at regular intervals.
  13. Once the mushrooms acquire a beautiful golden brown colour and turn a little crispy, season it with some salt and black pepper powder and mix well.
  14. Stir fry for a few more minutes then top it off with some fresh basil and turn off the heat.

For the sandwich:

  1. Generously butter a slice of bread.
  2. Line the buttered side of the bread with sufficient mushroom onion stuffing. 
  3. Top the layer of filling with a good generous layer of cheese. Let the butter, stuffing, and cheese be more but not less.
  4. Place the second slice of bread on top and press the sandwich gently.
  5. In a pan, melt some butter. 
  6. Place the sandwich on the pan and grill it on both sides until golden brown and crispy.
  7. Cut it in half or serve it as is. 

cheesy mushroom onion sandwich

One bite of this sandwich, and you will never look for another mushroom sandwich recipe. I am a big-time mushroom fan hence this sandwich tops my list. You have to try this out because it’s just too good to be missed. Serve it with a glass of fresh juice and some chips or fries to make a perfect filling meal. Feel free to improvise according to your preferences and create wonders!

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