Vegetarian Boursin Stuffed Portobello Mushrooms

These vegetarian boursin stuffed portobello mushrooms take your favorite two bite appetizer and turn it into a meatless main dish! Loaded with protein, veggies, and flavor, this vegetarian stuffed mushroom recipe will keep you satisfied on weeknights and holidays alike.

Three vegetarian boursin stuffed mushrooms on a white plate next to a glass of white wine and another white plate of stuffed mushrooms.

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Ingredients
How to make vegetarian boursin stuffed portobello mushrooms
Top tips
FAQ
More vegetarian main dish recipes
Recipe

In a meat and potatoes world, it can be hard to know what to serve as a vegetarian main dish or protein.

Stuffed mushrooms offer a flavorful option that is filling and offers a lot of nutritional value. I'm stuffing these mushrooms with a mixture of vegetables, cheese, and walnuts for a well balanced meal that gets better with every bite.

These are easy enough to make on a weeknight, but taste special enough to serve at Easter or Thanksgiving. Meat eaters will also appreciate them as a side dish or accompaniment to their meal.

Ingredients

Portobello mushrooms
Walnuts
Olive oil
Yellow onion, diced
Garlic, minced
Spinach, chopped
White wine, optional
Breadcrumbs
Fresh rosemary
Fresh sage
Fresh thyme
Coarse kosher salt and freshly ground black pepper
Garlic and Fine Herbs Boursin cheese

How to make vegetarian boursin stuffed portobello mushrooms

Heat the oven to 400ºF. Line a rimmed baking sheet with parchment paper. Set aside.
In a food processor, pulse walnuts until they're about the size of your breadcrumbs. Set aside.
Remove the stems from the mushrooms, but don't discard them. Finely chop the stems as well as two of the mushroom caps.
Place the whole mushroom caps stem side down on the prepared baking sheet and bake for 10 minutes.
While the mushrooms are in the oven, heat the oil in a large skillet over medium heat.
Once hot, add the chopped mushrooms and onion and cook, stirring occasionally, for 5 minutes or until softened.
Add the garlic and cook, stirring, for 1 minute.
Add the chopped spinach and cook, stirring, for 1 minute more.
Add the wine, if using, and stir. Lower the heat, and simmer for 5 minutes or until reduced by over half.
Remove from the heat and season with salt and pepper to taste, then add the walnuts, breadcrumbs, and Boursin. Stir to combine completely.
Remove the mushrooms from the oven and turn them over, stem side up. Using two large spoons, form the filling to fit into the mushroom caps, pressing it together and rounding the tops as needed. You can do this with your hands if you prefer.
Return the mushrooms to the oven and bake for 15 minutes. Serve warm.

Breadcrumbs and walnuts pieces in a bowl.

Mushroom stems, onions, and garlic cooking in a skillet.

Top tips

How to clean mushrooms

I don't recommend rinsing mushrooms with water because it can affect the taste and texture. You may find your mushrooms come with a little dirt clinging to them, so just use a damp cloth to wipe this dirt away before cooking with them.

Cooking with wine

This recipe calls for ½ cup of white wine. I usually choose pinot grigio for cooking, but whatever you have on hand will be fine.

The vegetables simmer with the wine for a few minutes, allowing the alcohol to cook off and leaving a delicious flavor and aroma. This makes it suitable to serve to children, however those sensitive to alcohol or recovering addicts may want to skip this step, and do not need to make any substitutions.

Boursin stuffed mushrooms on a sheet pan before baking.

Boursin stuffed mushrooms on a sheet pan after baking.

What to serve with stuffed mushrooms

How to store

Keep leftovers in a covered container in the refrigerator for up to 3 days. You can freeze stuffed mushrooms before or after baking, but may get a better result if freezing before baking.

To freeze, place stuffed mushrooms on a parchment lined baking sheet and place in the freezer until firm. Transfer to a freezer safe container or zip top bag and freeze for up to 3 months.

Three vegetarian boursin stuffed mushrooms on a white plate, one cut in half to reveal the inside.

Tips for customizing stuffed portobello mushrooms

Swap the boursin for dairy free boursin or a flax egg to make vegan stuffed portobello mushrooms
Meat eaters could use more mushroom caps and add cooked, crumbled sausage
Leave out the walnuts for a smoother filling
Swap the fresh spinach for frozen, thawed spinach in the amount of your choosing
When the mushrooms are done cooking, add a handful of fontina cheese to the tops and broil until melted and just beginning to brown

Three vegetarian boursin stuffed mushrooms on a white plate

FAQ

What is boursin?

Boursin is a type of gourmet cheese that is both creamy and crumbly. It is similar in texture to cream cheese, and comes in a variety of flavors combining savory herbs, garlic, onions, shallots, and peppercorns.

What kind of mushrooms should I use for stuffed mushrooms?

Portobello mushrooms (or the baby version, sometimes called cremini mushrooms) are ideal for using in stuffed mushroom recipes because they are naturally shaped in a way that makes them easy to stuff. They usually have a cap that curves and creates a nice pocket underneath for holding the filling. Occasionally portobello mushrooms grow a bit flat, so take note of this and look through what is available at the grocery store.

Can I make this recipe with cremini mushrooms?

Yes, you could make a smaller, appetizer sized version of this recipe using cremini mushrooms instead of large portobello caps. You would likely need four times as many mushrooms as called for in the recipe due to the smaller size.

How many stuffed portobello mushrooms should I plan per person?

If serving this as a main dish, you may want to plan on two mushrooms per person. They are rather filling, so some people may only want one. If serving this as a side dish, it's safe to plan on one mushroom per person.