Garlic Butter Portobello Mushrooms are a savory 20-minute side dish. Portobello mushrooms are cooked until golden and caramelized, then topped with toasted breadcrumbs and Parmesan for an easy recipe that’s packed with rich, earthy flavor.

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Holly’s Recipe Highlights: Portobello Mushrooms

- Flavor: These savory mushrooms are made with buttery garlic, aromatic thyme, and a crisp, golden breadcrumb topping that adds a delicious crunch.
- Why Make It: Ready in 20 minutes, without turning on the oven, this side dish pairs with almost anything!
- Serving Suggestions: I love serving these mushrooms alongside teriyaki pork tenderloin, grilled chicken, or garlic butter steak bites.
Total Time: 20 Mins Servings: 4 Cooking Method: Skillet

Ingredient Notes
- Portobello Mushrooms: Choose firm mushrooms with smooth, dry caps and no slimy spots. Wipe them clean with a damp paper towel, then remove the gills for a better texture and a cleaner-looking dish.
- Butter: Dividing the butter allows the breadcrumbs to toast until rich and golden, while the remaining butter creates a flavorful garlic finish.
- Panko Breadcrumbs: Toasting the breadcrumbs before adding them to the mushrooms keeps the topping light, crisp, and golden. Regular breadcrumbs can be used, but the topping will have a finer texture and less crunch.
- Parmesan Cheese (optional): Adds a savory, salty, nutty flavor to the crispy topping.
Variations
- Finish the mushrooms with a squeeze of fresh lemon juice or a splash of balsamic vinegar.
- Add a pinch of red pepper flakes with the garlic for a little heat.
- Swap the thyme for rosemary, parsley, or Italian seasoning to change the flavor.
How to Make Portobello Mushrooms
- Prep the mushrooms and toast the Panko toppings (full recipe below).
- Cook the mushrooms in olive oil with thyme, then add the remaining ingredients.
- Finish by topping them with toasted breadcrumbs and Parmesan before serving.

Saving Every Bite
Keep leftovers in an airtight container in the refrigerator for up to 4 days. Do not freeze.
Reheat in a skillet over medium heat until warmed through, adding a small pat of butter if they seem dry. The crumb topping will soften in the fridge, so add fresh toasted Panko before serving if you want the crunch back.
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Did you enjoy the following Portobello Mushrooms Recipe? Leave a comment and rating below.

Portobello Mushrooms
Ingredients
- 2 tablespoons butter divided
- 2 tablespoons Panko bread crumbs
- 3 large portobello mushrooms
- 1½ tablespoons olive oil
- ¼ teaspoon dried thyme leaves
- 1 clove garlic minced
- 1 tablespoon grated Parmesan cheese optional
Instructions
- Add 1 tablespoon butter and panko crumbs to the pan over medium heat. Cook while stirring until lightly toasted. Place in a dish and set aside.
- Wipe mushrooms clean with a damp paper towel. Use a spoon to scrape and gently remove the gills underneath. Slice mushrooms ¼" thick.
- Heat olive oil in a frying pan over medium high heat. Add thyme and mushrooms stirring just to mix.
- Cook mushrooms 4 to 5 minutes without stirring or until caramelized on one side. Stir and continue cooking until mushrooms are cooked. Add 1 tablespoon butter, garlic, salt, and pepper to taste. Cook 1 minute more.
- Sprinkle Panko crumbs over mushrooms (with parmesan cheese if using) and serve.
Notes
Nutrition Information
Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.
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Love your recipes. Tried it with blue cheese, equally delicious. Thank you for another winner
I also add fresh Parsley as well as fresh Thyme. I sauteed fresh carrots, celery, red onion and cloves of Garlic. Then mix well in mixer after sauteed. Mix crab meat in and too with parmesan and mozzerella. Cool until golden brown. Serve immediately. Delicious Valentine’s meal for my hubby and me.
Is it possible to make and then freeze? I’m looking for side dishes that are easy to pull out on vacation.
Hi Jenna, we have not tried freezing and reheating this recipe so I am not sure how it would turn out. The mushrooms may end up too moist. But if you do attempt it I would wait to add the panko and butter mixture until reheating.
Do you use fresh or dried thyme? I want to make these for Easter.
The measurement is for dried thyme leaves. You could use fresh too, I’d increase to about 1 teaspoon. Enjoy Amy!
Thank you! Would they taste better with fresh thyme?
I love using fresh if I have it on hand. You’ll notice it’ll be more fragrant.
This recipe IS delicious! I searched for a recipe to add pazzazz without having to stuff the mushrooms. This worked perfectly. I particularly liked adding the Panko bread crumbs and parmesan cheese. Yummy!
Absolutely delicious! I didn’t have thyme and used rosemary instead and it turned out just fine.
The key is to add the butter, garlic and salt & pepper at the end.
Very tasty.
Loved it! This was the first time I had sauteed fresh cremini mushrooms and loved them with a side of chicken Caeser salad. Easy and I enjoyed it.
Absolutely loved it! The parmesan is a must. The panko and parm were a delicious topping. Will be making this again!!!
Perfect !!! Love it !!!
Tough as nails. I think the mushrooms should have been sauteed in the butter and garlic from the beginning. Very disappointed.
Hi Patricia, sorry to hear that! This recipe is always a hit with readers. In step 4 you do want to continue cooking until the mushrooms are cooked. It sounds like your mushrooms may have need some additional time to cook fully. Hope that helps!
Patricia….I’m guessing you didn’t read the second sentence in this part of the recipe!!!!
“Cook mushrooms 4-5 minutes without stirring or until caramelized one one side. Stir and continue cooking until mushrooms are cooked.”
I followed your recipe, substituted pre-minced garlic to save some time. Served it as an appetizer on sliced sourdough bread. People were licking their fingers and the plate. Remarkable recipe, served it with a chardonnay wine. It was a big hit with guests. Thank you very much!!!
I love the idea of serving this as an appetizer! So glad your guests loved it!
Delicious as a vegetarian meal or with pork. I served with a Balsamic Glaze.
So glad you enjoyed this recipe Mary!
Great recipe, I wouldn’t change a thing. I appreciate your suggestions about using it with other meats, or as a topping on crusty bread. This was a delicious side dish, I served it with balsamic grilled chicken breasts and roasted asparagus.
Oooo, that sounds delicious Joan!
sounds delichous!
I hope you love it if you try it Sherry!
I could just eat bowls of these mushrooms. My fav way to have them is on toast with a fried egg
That sounds delicious, we love these as a side dish too!
Ooh! I love mushrooms and these look delicious. I didn’t know all those tips and tricks about cooking with portobello mushrooms. I’ll give them all a try next time I cook up some mushrooms
Thank you, I hope you enjoy the recipe!
Great post with great tips, my husband is going to love this recipe!
Enjoy Mikayla!
I think this would be the perfect addition to pork tenderloin or baked chicken breasts! The question is which one?!
Both! I love serving them next to pork, chicken, and steak!
This looks so good! Great for a topping on a nice steak or even as a side all its own!
They’re great on steak, enjoy!