Can you make this sandwich vegan?

Yes! You would need to make the following changes: omit the cheese or switch to a plant-based cheese, use a different bread (this bread has cheese), and use a vegan mayo instead of regular.

Could I make this with meat?

Yes - as I mentioned, my friend Ang originally made a similar sandwich using roast beef. So that's what I'd opt for if you want to skip the mushrooms!

What other bread would you recommend if I can't access the Trader Joe's focaccia?

A plain focaccia would still be delicious, or some fresh-sliced sourdough bread. If you want that onion flavor still, I would add caramelized onions to the sandwich too. Yum!

Could I use a different seasoning than Cajun seasoning?

Sure! You could use just about anything, even just some garlic/onion powder and salt and pepper.

Where do you buy pesto rosso?

I can usually find it at ALDI and Trader Joe's. Target also sells a red pesto that would work! This tomato and calabrian chile spread would also be FAB. (affiliate links)

Could I sauté the mushrooms instead of roasting?

Yes, but they will retain more moisture than roasting does, so I would pour off some of the liquid as you cook so that they don't soak the bread.

What type of mushroom is best for this sandwich?

Portobello mushrooms are my pick for this sandwich! They're the perfect thickness and so, so delicious.

Roasted Mushroom Sandwich with Horseradish Aioli Recipe

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

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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