As an Amazon Associate I earn from qualifying purchases.

This Portobello Mushroom Sandwich is made with creamy sweet potato, avocado and tomato slices, pesto, and tender portobello mushrooms coated with a coffee rub that’s unbelievably delicious! All you need is 1 hour to prepare this wholesome, plant-based main and up your sandwich game.

completed Portobello Mushroom Sandwich with Coffee Rub against a white surface

If you love Portobello Mushroom PizzasRoasted Mushrooms, and Stuffed Mushrooms, get ready to say hello to your new favorite global sandwich! 

Want to save this recipe?
Enter your email & get this sent to your inbox! Plus you’ll get great new recipes from us every week!

Why You’ll Love This Portobello Mushroom Sandwich

  • Perfect for Meatless Mondays. ​If your family or friends are new to eating plant-based, this portobello mushroom sandwich is a great place to start. The tender texture of portobello mushrooms is loved by almost everyone.
  • Hearty enough to keep you full. This portobello mushroom sandwich recipe is proof that plant-based vegetarian sandwiches and veggie burgers don’t have to be boring. This sandwich is stuffed with healthy carbs, roasted mushroom caps, healthy fats, and toasted bread and will keep you feeling satisfied until your next meal. 
  • Easy to customize. This portobello burger sandwich is an easy recipe to customize to suit your preferences and fridge. 

The Ingredients

The ingredients listed for this Portobello Mushroom Sandwich may appear long, but as you’ll quickly learn, so many of the ingredients are customizable. Use these ingredients as a recommendation and adjust to suit your own personal taste buds. 

ingredients for Portobello Mushroom Sandwich with Coffee Rub measured out against a white surface
  • Portobello mushrooms: Two large portobello mushrooms will make 2-4 hearty sandwiches, depending on the size of your bread and hunger level. Feel free to adjust this amount based on the amount of sandwiches you’ll need. 
  • Sweet potato: Adds a creamy sweetness, a variety of texture, and additional dietary fiber. 
  • Onion: White, yellow, and red onion slices will work. 
  • Avocado pestoIn addition to using this pesto on pasta, it’s delicious spread on these sandwiches. 
  • Avocado + tomato: Adds freshness and additional healthy fats. 
  • Sandwich rolls: Use any sandwich rolls or bread of choice. Most store-bought breads are naturally plant-based, but read the ingredients list to be sure, or make fresh whole grain bread or vegan burger buns from scratch. 

​Coffee Rub

  • Ground coffee: Dark roast coffee beans are best for their bold, robust flavor. Avoid flavored coffees. 
  • Sugar: Any sugar in the raw can be used. Granulated cane sugar, light brown sugar, coconut sugar, or dark brown sugar will work. 
  • Dried spices: You’ll need fennel seeds, ground coriander, coriander seeds, cumin, and thyme. 

Add-ins and Substitutions

There are so many options when it comes to customizing a homemade sandwich. Below are some of my favorite ideas, but is by no means a comprehensive list! 

How to Make a Portobello Mushroom Sandwich

  • 1) First, cook the potatoes until fork tender. With a fork or knife, poke a few holes around the outside of the sweet potato. Cover with foil and bake for about 40 minutes.

If you are short on time, there are two methods that will cook your sweet potatoes in a fraction of the time! Try my fast microwave method, or slice the sweet potatoes into rounds before baking and increase the oven temperature to 425F. This will cut the cook time down from 40 minutes to 15 minutes! 

  • 2) While the sweet potatoes roast, prepare the coffee rub. In a spice or coffee grinder, add the coffee along with the sugar, fennel seeds, ground coriander, coriander seeds, cumin, and thyme. Grind until a fine powder forms. 
  • 3) Using a wet cloth, wipe the portobello mushrooms down to clean them and moisten the outside. Liberally rub the coffee rub spice mixture on both sides of the mushrooms, as well as the sliced onion. Place the mushroom caps and the sliced onions on a parchment lined baking sheet and bake for 25 minutes. 
  • 4) As the mushrooms and onion roast, use this time to prepare the remainder of your sandwich fillings. I like to use tomato and avocado slices, plus my homemade Avocado Pesto as a sauce, but feel free to add whatever you’d like. 
  • 5) Once the sweet potato is tender and the portobello caps and onions are cooked through, begin to prepare to assemble. If the sweet potatoes were cooked whole, carefully remove the skin and chop the potatoes into 1/4″ round slices. Then, slice the portobello mushrooms on an angle.
  • 6) Spread on sandwich rolls or on sandwich bread with your desired vegan condiments and layer on the sweet potato rounds, mushrooms, and onions. Enjoy! 

Recipe FAQs

Is it okay to eat the gills of a portobello mushroom?

It is perfectly safe to eat the gills of a portobello mushroom. Some recipes will call for removing the gills, but this is purely preference and can be recommended for aesthetic reasons. I personally enjoy the additional hearty, earthy flavor the gills provide. 

What kind of bread is best for this sandwich?

I recommend a sturdier sandwich bread such as ciabatta, sourdough, a sliced french loaf, or a good-quality sandwich bread that can withstand the juicy mushrooms without becoming soggy. Our everyday sandwich bread would work well if it was toasted! 

How do I prevent my sandwich from becoming soggy?

One way is to lightly toast the bread. This helps to create a barrier and prevents moisture from soaking into the bread as easily. Additionally, you can use lettuce leaves layered closest to the bread slices to prevent the softer sandwich ingredients from touching the bread.  

 

Top Recipe Tips 

  • Don’t rinse your mushrooms! Mushrooms are incredibly water absorbent and and will absorb a lot of that excess moisture. Instead, simply wipe the mushroom tops and gill side lightly with a damp paper towel to remove any excess dirt. 
  • Toast the bread. ​In addition to preventing the portobello sandwich from becoming soggy, toasting the bread adds flavor, texture, and an amazing hearty crunch that contrasts the tender sweet potato and juicy portobello. 
  • Coat the mushrooms well. After preparing the coffee rub, generously season the mushrooms on both sides for the best flavor. If you find the coffee rub is having trouble sticking to the top of the mushrooms, you can lightly rub the mushrooms with olive oil before coating. 
completed Portobello Mushroom Sandwich with Coffee Rub against a white surface

Serving Suggestions 

These hearty sandwiches are wholesome enough to enjoy on their own as a stand-alone lunch or dinner, but can always be paired with additional plant-based sides to round out the meal! Here are a few of my favorites that are perfect for vegan lunches on-the-go: 

Make Ahead Tips

If you are making this portobello mushroom sandwich for meal prep, I’d recommend storing all of the toppings, condiments, and bread separately and assemble right before eating. 

Or, if you’d like to prepare the sandwich the night before, make sure to toast the bread to help prevent sogginess. 

More Veggie Sandwich Recipes 

Photos by Alfonso Revilla

completed Portobello Mushroom Sandwich with Coffee Rub against a white surface

Portobello Mushroom Sandwich with Coffee Rub

5 from 2 votes
Prep: 20 minutes
Cook: 30 minutes
Total: 50 minutes
Servings: 4 servings
This Portobello Mushroom Sandwich is made with creamy sweet potato, avocado and tomato slices, pesto, and tender portobello mushrooms coated with a coffee rub that's unbelievably delicious! All you need is 1 hour to prepare this wholesome, plant-based main and up your sandwich game.

Ingredients 

  • 1 sweet potato
  • 1 ½ tablespoons of ground coffee
  • 1 tablespoon of sugar in the raw
  • ¼ teaspoon of fennel seeds
  • ¼ teaspoon of ground coriander
  • ¼ teaspoon of coriander seeds
  • ¼ teaspoon of cumin
  • ¼ teaspoon of thyme
  • 2 portobello mushrooms
  • ½ of an onion (sliced thinly for a sandwich)
  • ½ cup of avocado pesto
  • 1 avocado
  • 4 sandwich rolls (or your favorite bread)

Instructions 

  • Preheat oven to 375.
  • With a fork or knife, poke a few holes on the sweet potato. Cover with foil and bake for about 40 minutes. (or microwave for 7-10 minutes with no foil)
  • In a spice or coffee grinder, add the coffee and spices. Grind until a fine powder. Using a wet cloth, wipe down the mushrooms to clean them and get them a little moist. Liberally rub the spice mixture on both sides of the mushroom. Add the spice rub to the onions. Place on a parchment paper lined baking sheet and bake for 25 minutes.
  • Slice the tomato and avocado.
  • When the potato is tender, remove the foil and skin. Chop into ¼ inch round slices. Slice the mushroom on an angle. Assemble the sandwiches and enjoy!

Notes

  • Don’t rinse your mushrooms! Mushrooms are incredibly water absorbent and and will absorb a lot of that excess moisture. Instead, simply wipe the mushroom tops and gill side lightly with a damp paper towel to remove any excess dirt. 
  • Toast the bread. ​In addition to preventing the portobello sandwich from becoming soggy, toasting the bread adds flavor, texture, and an amazing hearty crunch that contrasts the tender sweet potato and juicy portobello. 
  • Coat the mushrooms well. After preparing the coffee rub, generously season the mushrooms on both sides for the best flavor. If you find the coffee rub is having trouble sticking to the top of the mushrooms, you can lightly rub the mushrooms with olive oil before coating. 

Nutrition

Calories: 444kcalCarbohydrates: 54gProtein: 10gFat: 22gSaturated Fat: 3gPolyunsaturated Fat: 2gMonounsaturated Fat: 6gTrans Fat: 0.003gCholesterol: 2mgSodium: 639mgPotassium: 676mgFiber: 8gSugar: 9gVitamin A: 8722IUVitamin C: 8mgCalcium: 136mgIron: 3mg

Disclaimer: Although plantbasedonabudget.com attempts to provide accurate nutritional information, kindly note that these are only estimates. Nutritional information may be affected based on the product type, the brand that was purchased, and in other unforeseeable ways. Plantbasedonabudget.com will not be held liable for any loss or damage resulting for your reliance on nutritional information. If you need to follow a specific caloric regimen, please consult your doctor first.

Additional Info

Course: Dinner, Lunch
Cuisine: American
Method: Oven
Diet: Vegan
Tried this recipe?Please tag us at @PlantBasedOnABudget! 🙂
About

David Sterkel

Plant based foodie, running, cooking, trash TV- all things that describe me! I enjoy cooking quick and easy meals that are healthy and inexpensive. Happy reading!

More about David Sterkel

Leave a comment

Your email address will not be published. Required fields are marked *