These easy stuffed portobello mushrooms with spinach, feta and sautéed garlic are marinated in balsamic vinegar and make an absolutely perfect veggie side dish, or even first course! With only a few main ingredients, you’ll find these mushrooms don’t require any other bells and whistles to be fabulous, flavorful show stoppers.
They’re vegetarian (when using vegetarian feta), gluten-free, keto and packed with leafy green vitamins and minerals!
It’s March and spring is right around the corner – with all my spring clothes from last year that I hope to fit into after a very buttery, breaded, pumpkin spice snickerdoodley Fall and Winter. Time to slim down in the healthiest way I know how – with all those wonderful leafy green nutrients… and a little bit of feta.
I love serving stuffed portobello mushrooms as a first course at a dinner party. They can easily be made ahead of time, they look so enticing and also make a perfect complement to an entree like roasted duck or beef bourguignon!
How to Make These Stuffed Mushrooms – Step by Step
1. Preheat oven to 400 F. Remove as much of the portobello stems from 2 portobello caps as you can without damaging the caps. You don’t have to remove the mushroom gills. In a medium-size mixing bowl, pour ¼ cup olive oil and 1 tbsp. balsamic vinegar, and sprinkle with garlic powder and sage spice. Gently coat the mushrooms in the mixture and set aside to marinate.
2. Mince 4 garlic cloves and set aside.
3. Remove the stems from 3 cups of fresh spinach and coarsely chop. Set aside.
4. Add 3 tbsp. olive oil to a frying pan and brown minced garlic for 3-4 minutes.
5. Place chopped spinach right on top of the garlic and allow it to wilt down and sauté for 4-5 minutes. As it wilts, gently stir into the garlic and oil. Sprinkle with salt and pepper and set aside when done.
6. Place mushroom caps face down in a pyrex or baking sheet and bake for 10 minutes.
7. Remove pyrex and pour out any liquid if any released. Gently turn caps over and stuff with spinach.
8. Sprinkle about 3 tbsp. of crumbled feta cheese (1½ tbsp. each) on top of the spinach. Bake for 20 minutes more and serve.
Yes. They’re definitely edible, as well as the stems, but the stems have a thicker, more fibrous texture and you’ll want to carefully remove as much of them as you can to make room for the spinach and feta in this recipe.
You can also remove the gills if you want to make even more room, but it’s not entirely necessary.
Portobello mushrooms are also referred to as “portobella” mushrooms, and both are correct terms for the same kind of mushroom. It’s only a matter of size.
When the crimini mushroom is small, it’s referred to as a “portobella” or “baby bella” mushroom, and when they get bigger, they’re branded as “portobello” mushrooms. It’s as simple as that.
Yes you can, although fresh, sautéed spinach has more flavor pizzaz and a brighter green color that just makes for a prettier stuffed mushroom. However, it’s a misconception that frozen spinach is less nutritious.
Spinach is frozen at peak freshness and it’s nutrition doesn’t diminish, whereas fresh spinach will lose nutritional value while it wilts. So ideally, go for the very freshest spinach, but if you can’t find it, frozen will be just as healthy (just a little less green).
If you use frozen spinach, make sure to thaw and squeeze out as much water as you can. Brown your minced garlic then sauté thawed spinach in the olive oil and garlic for 4-5 minutes.
They certainly can! They won’t dry out and the feta won’t melt or become burnt. Simply reheat mushrooms at 350 F. for 10-15 minutes. Stuffed mushrooms will stay perfectly tasty for 2-3 days if stored in a container with a tight lid and refrigerated.
A Little More Veggie Side Dish Inspiration
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Stuffed Portobello Mushrooms with Spinach and Feta
- sharp knife and cutting board
- frying pan
- wooden spoon or spatula
- medium-size mixing bowl
- glass pyrex or foil-lined baking sheet
- 2 portobello mushroom caps
- 3 cups fresh spinach – chopped
- 4 garlic cloves – minced
- 3 tbsp. feta cheese – crumbled
- 1 tbsp. balsamic vinegar
- garlic powder – just a sprinkle
- sage spice – just a sprinkle
- salt & pepper – to taste
- ¼ cup olive oil – for marinade, and 3 tbsp. for pan
- Preheat oven to 400 F. Remove as much of the portobello stems from 2 portobello caps as you can without damaging the caps. You don’t have to remove the mushroom gills. In a medium-size mixing bowl, pour ¼ cup olive oil and 1 tbsp. balsamic vinegar, and sprinkle with garlic powder and sage spice. Gently coat the mushrooms in the mixture and set aside to marinate.
- Mince 4 garlic cloves and set aside.
- Remove the stems from 3 cups of fresh spinach and coarsely chop. Set aside.
- Add 3 tbsp. olive oil to a frying pan and brown minced garlic for 3-4 minutes.
- Place chopped spinach right on top of the garlic and allow it to wilt down and sauté for 4-5 minutes. As it wilts, gently stir into the garlic and oil. Sprinkle with salt & pepper and set aside when done.
- Place mushroom caps face down in a pyrex or baking sheet and bake for 10 minutes.
- Remove pyrex and pour out any liquid if any released. Gently turn caps over and stuff with spinach.
- Sprinkle about 3 tbsp. of crumbled feta cheese (1½ tbsp. each) on top of the spinach. Bake for 20 minutes more and serve.
Can large white mushrooms be used instead of portobello?
I believe so. I haven’t used them with this recipe myself, but I believe the cook time will be about the same. I would maybe suggest using chopped spinach, to make it easer to stuff smaller mushrooms.
How are you calculating these at 371 calories per mushroom. I put all of the ingredients in my calorie tracker and I’m coming up with 87 calories granted I am using low calorie balsamic. But even with balsamic vinegar that only adds a few more calories? At any rate I’m excited to try this recipe tonight!
Hi Meg! You know what? I think my calorie calculator included the full ¼ cup of olive oil (477 calories!) even though it’s just for a marinade. I think it split that between the 2 mushrooms. Thank you so much for bringing that to my attention! I re-ran the calculation, so it’s much more accurate now.
No problem! I did forget to add the olive oil so mine was incorrect too lol. Can’t wait to have these for dinner tonight!
Hope you enjoy them, and thanks again!
Just made these as a side for my salmon and holy cow! These are going in my rotation for sure. Made exactly as the recipe states…so SO good!!!
Thank you, Maria! What a sweet comment. So glad you liked it!
Made these tonight, delicious! Thanks for sharing!
Loved it. Easy and quick. I would cook mushrooms for 10 minutes while preparing the spinach mixture.
These turned out delicious! So simple and easy but big on flavour. Loved the idea of doing a quick marinade. Thank you! 🙂
Thank you, Monique! So happy you liked them!