Stuffed Portobello Mushrooms

Enjoy stuffed portobello mushrooms packed with mashed potatoes, fragrant garlic, capers, and sundried tomatoes. The perfect meatless recipe!

From the delicate, oversized mushrooms to the fluffy mashed potatoes that melt in your mouth, this is the ultimate stuffed Portobello mushrooms recipe.

Every single layer gives you another reason to fall in love with these large stuffed mushrooms. They’re hearty enough to be a main dish and we love how easy they are to make. Grab a couple of portobellos and let’s make something delicious!

What Are Portobello Mushrooms?

These are massive, edible mushrooms that you’ve probably seen in the grocery store before! Because of their size, they’re a wonderful substitution for grilled meats. Portobello mushrooms also have a natural cavity that works perfectly to fill with tasty ingredients (in this case, mashed potatoes!). Choose the largest mushrooms you can find, keeping in mind that they shrink considerably during baking, and remove the gills before filling them. 

Tips For Baking Portobello Mushrooms

This is a fairly simple recipe, but please follow these tips when you make them. It will help them go from delicious to palate perfection!

For the best results, you should pick the largest Portobello mushrooms that you can. As you can see in the picture below, they shrink when they bake, so the larger the better.

As they bake, they will release liquid into the pan. Discard all of this liquid before you serve them.

How To Make Meatless Stuffed Portobello Mushrooms

All of the exact steps for the recipe are in the printable recipe card at the bottom of the post.

First, here are some photos of each step of the process so you can see how I made them. I'll even include extra tips along the way too.

How to Remove Portobello Mushroom Gills

The very first thing you'll do is prepare the portobello mushrooms. Cut off the stems and use a spoon to gently scrape out the gills that line the cap of the portobellos. Be careful not to crack or puncture the mushroom or your filling might leak out! You can do this step in advance if you want to meal prep a little bit and save some time before cooking. To wash portobellos, gently wipe them with a damp paper towel to remove dirt and then rinse them in cold water.

This is a very important step because you are turning the mushrooms into a bowl that will hold the mashed potato filling.

Then, we baked the mushrooms before we stuffed them. Brush the tops of the mushrooms with olive oil and place them stem-down on a baking sheet, like in the photo above.

Roast unpeeled garlic at the same time as the mushrooms. Wrap the garlic cloves in aluminum foil and place them on the baking sheet with the mushrooms.

This is when you will notice liquid in the pan. Remove the mushrooms and discard the liquid, and then put the garlic cloves back in the oven to roast for about 15 more minutes.

Make The Mashed Potato Filling

Start prepping the mashed potato filling while the mushrooms are cooking.

Peel the potatoes completely so that you won't have any bits of potato skin in the filling.

Then, cut them up into 2-inch large pieces. The smaller the pieces, the faster they will soften as they boil.

Place the potatoes into a saucepan and put water at least 2 inches above the potatoes. This water should be very salty - We used ½ teaspoon of salt in it.

After the potatoes are nice and soft, keep about 1 cup of the potato water and then drain the potatoes.

Do this next part very quickly. The potatoes will mash better when they are nice and hot! Add the peeled roasted garlic cloves, salt, and pepper.

Add the potato water a little at a time. This prevents the mashed potatoes from becoming too runny. Make sure to add liquid to the mashed potatoes a little bit at a time so they aren’t too loose. They should be thick and creamy, not runny or watery!

Alternatively, you can use an unsweetened, non-vanilla plant-based milk to thin the potatoes too.

After your mashed potatoes have the consistency you want, add the capers and sundried tomatoes and mix them together really well. Instead of capers, you can use olives.

Fill The Mushrooms & Add Toppings

Now you are ready to place the filling into the Portobello mushrooms. Top the mashed potatoes with either store-bought marinara sauce, spaghetti sauce, or pizza sauce. Add some shredded mozzarella cheese and feta cheese.

Bake it again for 15 minutes - just long enough for the cheese to melt! Perfection.

Vegan Stuffed Portobello Mushroom Recipe

To create vegan mashed potatoes, add any kind of unsweetened (non-vanilla!) plant-based milk. Regular milk works fine if you aren’t avoiding dairy. Mash the potatoes while they’re still hot to create the fluffiest, creamiest vegan filling! You could also choose to fill the portobellos with Carrot Raisin Quinoa for a more veggie-packed spin on this recipe, or make portobello pizzas with tomato sauce, cheese, and oregano on top.

Other Recipes With Portobello Mushrooms

Portobello mushrooms are a family-favorite in this house. Here are some more of our favorite recipes that use them.

• Winter Squash Salad With Portobello Mushrooms
• Coconut Miso Ramen
• Grillable Veggie Burger
• Shawarma Veggie Tacos
• Vegan Lasagna Soup

DID YOU LIKE OUR STUFFED PORTOBELLO MUSHROOM RECIPE?

If you enjoyed this recipe, it would help us tremendously if you left us a star rating in the comments below or on the recipe card. Do you have any questions about the recipe? Do you need a swap for any of the ingredients? We are here to help, just leave us a question in the comments below.

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