This caramelized onion mushroom flatbread is loaded with flavorful caramelized onions and mushrooms, two kinds of cheese, and lots of peppery arugula on top.

Flatbreads are definitely underrated in the appetizer department, but we’re giving them the spotlight to shine today and loading them up with the WORKS!
This is one of those situations where you may very well make your appetizer your dinner cause, I mean LOOK at these babies.

Unsurprisingly, mushrooms are a match made in heaven with caramel-y, golden onions and take all the flavors in this flatbread up to a 10/10!
Your app game isn’t about to know what even hit it.
This Caramelized Onion Mushroom Flatbread features…
- Flavorful Parmesan and gruyere cheese on tender flatbreads.
- Tender sweet onion and mushrooms.
- Peppery arugula and tangy balsamic glaze on top.

Making the Mushroom Flatbread
(scroll down to the bottom of the post for the full recipe)
Ingredients You Will Need
- Sweet onion
- Mushrooms
- Garlic
- Olive oil
- Unsalted butter
- Thyme
- Gruyere cheese
- Parmesan cheese
- Flatbreads
- Balsamic glaze
- Arugula
How to Caramelize Onions
You will need 1 medium sweet Vidalia onion in thin slices to make the caramelized onions for this flatbread.
The most important part about caramelizing is cooking the onions very slowly so you’re going to want to cook the onion over medium heat for about 20 minutes, stirring occasionally until they are a deep golden brown.
These onions store very well, so you can easily make them ahead of time and store in the fridge for recipes.

Tips for Perfect Flatbread
- Add mushrooms to onions at end of cooking – the mushrooms will only take a few minutes to cook, so we prefer to add them when the onions are almost done caramelizing.
- Use a pizza stone – for a crispy, tender flatbread texture you can’t beat baking these flatbreads on a pizza stone, however, if you don’t own a stone, a large sheet pan will work just fine.
- Top flatbreads with arugula and balsamic glaze – once the flatbreads are baked, we like to top them with lots of fresh arugula and a good drizzle of balsamic glaze for a last little punch of flavor.
Recipe Variations
Try these ideas for a different twist on this flatbread!
- Add more veggies – try sautéed zucchini, broccoli, spinach, or kale.
- Make it meaty – cooked chicken, bacon bits, or sausage would be great meaty additions.
- Try a different cheese – mozzarella, gouda, asiago, or provolone would be great stand-ins for the suggested cheeses.
- Make it a pizza – you can definitely make this flatbread into a full-size pizza. Just be aware that cook time will need to be increased.
What to Serve with Flatbread
This flatbread can definitely be served as a meal on it’s own, but it’s also amazing alongside a variety of other dishes as an app!
We love serving slices alongside a cheese board, chips and dip, and of course, lots of wine or our favorite beer!

The combination of the caramelized onions, tender mushrooms, and rich cheese on this flatbread is just an absolute flavor bomb and you’re going to be a huge fan.
Truthfully, we almost always make a meal out of this flatbread and don’t ever regret it!
Save this recipe using the ‘save to recipe box’ button below. If you make it, please let us know! Leave a comment + star rating below, or take a photo and tag it on Instagram with #wholeandheavenlyoven.

More flatbreads for you to try next!
Caramelized Onion Mushroom Flatbread
Ingredients
- 1 tablespoon olive oil
- 1/2 tablespoon butter
- 1 medium Vidalia sweet onion, thinly sliced
- 2 cups mushrooms, thinly sliced
- 2 medium cloves garlic, minced
- 1 tablespoon fresh minced thyme
- Salt and pepper to taste
- 1 cup shredded gruyere cheese
- 1/4 cup grated Parmesan cheese
- 3 medium naan flatbreads
- Balsamic glaze, fresh arugula, and additional grated Parmesan for serving
Instructions
- Preheat oven to 400F and place a pizza stone in oven to heat. (if you don't have a pizza stone, instead line a large baking sheet with parchment paper and set aside on counter)
- In a large skillet over medium heat, melt olive oil and butter, swirling pan to evenly coat. Add onions and cook over medium heat, stirring occasionally until onions are a deep golden brown, about 20 minutes.
- Add mushrooms, garlic, and thyme to pan and saute an additional 3-4 minutes or until mushrooms are softened. Season with salt and pepper to taste.
- Sprinkle cheeses over flatbread and top with caramelized onion/mushroom mixture. If using pizza stone, use a peel to slide flatbreads onto stone. If using baking sheet, transfer flatbreads to baking sheet.
- Bake flatbreads at 400F 10-12 minutes until edges of flatbread begin to crisp up and topping is lightly browned.
- Remove flatbreads from oven and top with balsamic glaze, arugula, and additional grated Parmesan cheese. Slice flatbread into wedges, serve warm, and enjoy!
Nikki says
WOW!! Loved this recipe ! I actually used cauliflower crust from Trader Joes and it worked perfectly. Such a delicious recipe and so easy and fun to make. Highly recommend.
Sarah says
I will have to try the cauliflower crust next time! Happy to hear you loved this flatbread, Nikki. 🙂