Ready in: 1 hour · Serves: 4 · Technique: Roasting · Storage: Up to 3 days in the refrigerator.
Quick Answer
This Roasted Mushroom Sandwich with Horseradish Aioli combines crispy mushrooms and creamy aioli for a comfort food delight perfect for any gathering.
One of my favorite things about living in New York City during this time of year is the way the crisp air encourages a cozy atmosphere, perfect for indulging in hearty comfort foods. As the holidays approach, I often find myself seeking recipes that are delicious yet easy to prepare for gatherings, and this Roasted Mushroom Sandwich with Horseradish Aioli fits the bill perfectly. It’s a crowd-pleaser, whether it’s for a casual lunch or a festive party.
A Cozy Holiday Treat

Why You’ll Love This Recipe
- Quick and easy to prepare, perfect for gatherings or a cozy lunch.
- Rich and earthy flavors from the mushrooms paired with zesty horseradish aioli.
- Customizable with different breads and greens to suit your taste.
- Can be made ahead of time, making entertaining a breeze.
- A delightful way to enjoy seasonal ingredients during the holidays.
Ingredients
Gather the following ingredients to make this delicious sandwich:
Mushrooms
- 2 cups mixed mushrooms (cremini and shiitake recommended)
- 2 tablespoons olive oil
- Salt and pepper to taste
- 1 tablespoon fresh thyme (or 1 teaspoon dried thyme)
Bread and Spread
- 1 sourdough baguette
- 4 tablespoons horseradish aioli
- Fresh arugula or spinach for garnish
How to Make Roasted Mushroom Sandwich with Horseradish Aioli (Step-by-Step)
This sandwich is simple to make but bursting with flavor. Follow these steps for a delicious result:
Step 1: Prep the Mushrooms
Start by preheating your oven to 400°F (200°C). Clean your mushrooms by gently wiping them with a damp cloth, then slice them thickly, about ½ inch. This ensures they roast beautifully.
Step 2: Season
In a large bowl, toss the sliced mushrooms with olive oil, a generous pinch of salt, pepper, and fresh thyme. The earthy aroma of thyme will enhance the mushrooms’ flavor, making your kitchen smell amazing!
Step 3: Roast
Spread the seasoned mushrooms in a single layer on a baking sheet lined with parchment paper. Bake for 20-25 minutes, flipping halfway through, until they’re golden brown and crispy around the edges. Look for that lovely caramelization.
Step 4: Build the Sandwich
While the mushrooms are roasting, slice the sourdough baguette into hearty pieces. Once the mushrooms are done, it’s time to assemble your masterpiece. Spread a generous layer of horseradish aioli on each slice of bread.
Step 5: Layer
Now, pile on the roasted mushrooms and finish off with a handful of fresh arugula or spinach. The peppery greens beautifully balance out the richness of the mushrooms.
Step 6: Serve
Enjoy your sandwich warm, and don’t hesitate to drizzle a bit more aioli on top if you’re feeling indulgent!

Common Mistakes to Avoid
- Overcrowding the Baking Sheet: Ensure the mushrooms are spaced out; overcrowding will steam them instead of roasting, leading to soggy mushrooms.
- Not Preheating the Oven: A properly preheated oven ensures the mushrooms roast evenly and develop a beautiful caramelization.
- Skipping Fresh Herbs: Fresh thyme brings a bright flavor that transforms the sandwich; don’t skip it!
Tips and Tricks for Success
- If you want to make this sandwich ahead of time, roast the mushrooms the day before and assemble just before serving.
- Try different bread varieties, such as ciabatta or multigrain, for added texture and flavor.
- For an extra kick, consider adding a few sliced pickles to your sandwich.
Variations
- Swap out mixed mushrooms for your favorites, such as portobello or oyster mushrooms.
- Use a different type of aioli, like garlic or spicy sriracha, for varied flavor.
- Substitute sourdough baguette with gluten-free bread or pita for dietary preferences.
- Add roasted red peppers or sun-dried tomatoes for additional sweetness.
How to Serve
- Enjoy your sandwich warm, with extra aioli drizzled on top for indulgence.
- Pair with a simple side salad or a warm soup for a complete meal.
- Serve at a gathering as a hearty appetizer or as part of a festive buffet.

Make Ahead and Storage
- Make Ahead: Roast the mushrooms the day before and assemble just before serving.
- Storage: Store leftover roasted mushrooms in an airtight container in the refrigerator for up to three days.
- Reheating: Reheat in the oven to revitalize the crunchy texture and bold flavor.
- Freezing: Not recommended for this recipe.
Recipe Notes / What I Learned
Testing this recipe taught me that simplicity can result in incredible flavor, especially with the right ingredients, like fresh thyme and quality mushrooms. I will definitely be making this sandwich for my upcoming holiday gatherings!
Yield and Serving Size
Yield: 4 sandwiches · Serving Size: 1 sandwich
Nutrition Snapshot
Estimated Nutrition Per Serving: ~450 calories · 10g protein · 50g carbs · 20g fat

Savory Roasted Mushroom Sandwich with Horseradish Aioli
Ingredients
Equipment
Method
- Preheat your oven to 400°F (200°C). Clean mushrooms by gently wiping them with a damp cloth, then slice them thickly, about ½ inch.
- In a large bowl, toss the sliced mushrooms with olive oil, salt, pepper, and fresh thyme.
- Spread the seasoned mushrooms in a single layer on a baking sheet lined with parchment paper. Bake for 20-25 minutes, flipping halfway through, until golden brown and crispy.
- Slice the sourdough baguette into pieces. Spread a layer of horseradish aioli on each slice and layer on the roasted mushrooms and fresh arugula or spinach.
- Enjoy your sandwich warm with additional aioli if desired!
Notes
FAQs
Can I use different types of mushrooms for this sandwich?
Absolutely! While cremini and shiitake offer a rich flavor, you can experiment with other mushrooms like portobello, oyster, or button mushrooms to suit your taste.
What can I serve with the Roasted Mushroom Sandwich?
This sandwich pairs well with a simple side salad, sweet potato fries, or a warm soup, making it a versatile option for any meal.
How do I make homemade horseradish aioli?
You can make homemade horseradish aioli by combining mayonnaise, grated horseradish, lemon juice, garlic, and a pinch of salt in a bowl. Adjust the horseradish to taste for more or less heat.







