Layers of roasty mushrooms, havarti, lemony arugula, and an easy homemade horseradish aioli make this mushroom sandwich a WINNER. A saucy, salty, hefty masterpiece!
Roasted Mushroom Sandwich with Horseradish Aioli
The Mushroom Sandwich That I Can’t Quit
Do I always talk about Ang or do I always talk about Ang?
Really, all my favorite food ideas come from Ang. Texas style chili, chicken wraps, and the famous tortellini soup.
I got a text a few weeks ago from Ang with a photo of her sandwich – like friends do – which was layers of roast beef, arugula, havarti, and horseradish aioli on the caramelized onion focaccia from Trader Joe’s. I spent at least 10 minutes just zoomed in on the photo, examining every saucy detail. Then I went and immediately made one for myself.
I was feeling called to a no-beef-but-still-beefy mushroom version, and it is beyond.
That horseradish aioli is pulled from the old fave portobello French dip recipe (5 star, so good), and the roasty mushrooms, havarti, and arugula create layers of flavor that were just meant to be together. It might be over the top, but I also like a shmear of pesto rosso on the bottom of the focaccia so you can get a little tomatoey brightness in the mix.
Please go sink your teeth into this smushy, saucy, salty and hefty masterpiece. It is a good one.
How To Make This Mushroom Sandwich
1
Roast the mushrooms.
Toss the mushrooms with olive oil and a hefty sprinkle of seasoning (I use Cajun seasoning). Roast ’em up till they’re golden, chewy, and delicious.
2
Make that horseradish sauce.
Oh man, it’s so good. Mix your mayo, garlic, lemon, and horseradish together. Season with salt.
3
Toast and split the bread.
Would highly recommend the caramelized onion focaccia from Trader Joe’s for this one.
4
Layer your sandwich.
My layers: pesto rosso (also from Trader Joe’s, and optional), mushrooms, havarti cheese (melted for funs), arugula, and horseradish sauce on top.
5
You’re Done! Yum.
Devour and enjoy.
Watch How To Make This Mushroom Sandwich
Roasted Mushroom Sandwich with Horseradish Aioli
- Total Time: 40 minutes
- Yield: this makes enough mushrooms and sauce for 3-4 sandwiches
Description
Layers of roasty mushrooms, havarti, lemony arugula, and an easy homemade horseradish aioli make this mushroom sandwich a WINNER. A saucy, salty, hefty masterpiece!
Ingredients
Units
Scale
Roasted Mushrooms
- 16 ounces sliced mushrooms (portobello or white button mushrooms)
- 2 tablespoons avocado oil
- 2 tablespoons Cajun seasoning (if it has salt in it, you may want to add less of it just to make sure the mushrooms don’t get too salty – every brand is different)
- salt and pepper to taste
Horseradish Aioli
- 1/2 cup mayo
- 1 small clove garlic, grated (even half a clove is plenty)
- 1–2 teaspoons horseradish sauce, to taste (I use Boar’s Head)
- 1–2 teaspoons lemon juice, to taste
- salt, to taste
Sandwiches
- Big honking chunk of bread that you really love (I like Trader Joe’s caramelized onion focaccia for this)
- Pesto rosso (optional as a second sauce)
- Havarti cheese slices
- Arugula tossed with olive oil and lemon
Instructions
- Roast the mushrooms: Preheat the oven to 450 degrees. Toss the sliced mushrooms with the avocado oil and the seasoning on a sheet pan until well-combined. Roast for 20-25 minutes, until golden brown.
- Make the horseradish aioli: Mix all the sauce ingredients in a bowl until well-combined. Taste and season.
- Assemble the sandwiches: Toast the bread for the last few minutes on the pan with the mushrooms. Split the bread, spread with pesto rosso, roasty mushrooms, havarti (pop it in the oven again for a minute if you want it to melt), arugula, and the top piece of bread shmeared with the horseradish sauce. OH MY WORD can you even? This is so good.
- Prep Time: 10 minutes
- Cook Time: 30 minutes
- Category: Sandwich
- Method: No-cook
- Cuisine: American
Keywords: mushroom recipe, mushroom sandwich, focaccia sandwich, vegetarian sandwich
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December 11, 2023
Nice to meet you!
I’m Lindsay and I ♡ FOOD. I used to be a teacher, and now making food and writing about it online is my full-time job. I love talking with people about food, and I'm so glad you're here.
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Happy Monday Lindsay,
This mushroom sandwich recipe is a game-changer. The depth of flavors – the roasty mushrooms paired with the zesty horseradish aioli can virtually be smelled and felt by others who’ll read this beautiful food blog. Your creativity in the kitchen never ceases to inspire me. Thanks again Lindsay, for sharing another fantastic recipe that’ll keep everyone, including me, coming back for more. Can’t wait to see what you’ll cook-doctor up next. 🙂
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Made these tonight, yum yum yum!
DO NOT SKIP THE AIOLI (and the pesto Rosso took this sandwich over the top) whole family loved them 🙂
Thank you for this recipe
This is so incredibly good! I made it twice in three days. My husband asked where I got the recipe (which he never does).