Roasted Mushroom & Caramelized Onion Quesadilla

Roasted Mushroom and Caramelized Onion Quesadilla | Veggie and the Beast

I had a Facebook nightmare last week. Like an actual terrifying dream while sleeping. About Facebook. This makes me feel like a total crazy person.

To understand the horror, you must know that I used to journal every night in high school. I’ve since learned that journaling is not a positive, helpful, or healthy activity, but in high school I was all about writing down all my feelings, and teenagers have a LOT of feelings. Feelings for days. Pages and pages and pages of feelings.

Roasted Mushroom and Caramelized Onion Quesadilla | Veggie and the Beast

I dreamed that my current 28-year-old self had posted one of my high school journal entries on my Facebook page as a status. Willingly! What?

I cannot remember the details of the entry, and if I did I wouldn’t post them here (…because this is a nightmare, people) but I can assure you that it was filled with over-the-top Joey Potter-inspired prose, and lots of teenage-girl ramblings that no one should ever be subjected to after the age of 18 (or maybe ever?). In my dream I posted the entry, and then immediately regretted it, but I couldn’t delete it from my page, so it just lingered there for all to read.

To try to ease the stress of the situation, I (in my dream) went out to get coffee, only to realize that I had chosen the coffee shop where all of my high school classmates were hanging out. I’m shocked that I wasn’t naked, too, because that is the only thing that could have made that dream any more horrifying.

Analyze that, folks.

Roasted Mushroom and Caramelized Onion Quesadilla | Veggie and the Beast

Now that I’m a well-adjusted adult, I prefer to write about food instead of feelings. Well, maybe sometimes I write about my feelings. Right now I feel good! Really good, actually, because I ate some of this quesadilla for lunch…along with some peanut butter cream and a few bites of a black bean burger. Such is the life of a food blogger who needs to take advantage of natural light on weekends. It’s glamorous.

On a related note, you should see my kitchen…yikes.

Roasted Mushroom and Caramelized Onion Quesadilla | Veggie and the Beast

These quesadillas though. I go through phases with mushrooms, and we’ve been kind of on the outs for the last few months. Ryan has suggested making mushroom dishes several times, and I’ve resisted – the one who does the grocery shopping always wins, you know. When I actually felt a craving for savory roasted mushrooms, I thought I’d make this dish a total Ryan-pleaser by taking the mushrooms he’d been craving, and sandwiching them between lots of onions and lots of cheese.

If you’re not a swiss cheese fan, feel free to switch it up – mozzarella or fontina would be great here. I like how flavorful shiitake mushrooms are, but if you have regular white button mushrooms those will work as well. To make these gluten free, simply sandwich the filling between two small corn tortillas instead of one folded flour tortilla.

Roasted Mushroom & Caramelized Onion Quesadilla

A savory, rich quesadilla made with rosemary roasted mushrooms, caramelized onions, and melted swiss cheese.

Yield: 2 servings

Prep Time: 5 minutes

Cook Time: 45 minutes

Total Time: 50 minutes


  • 1 large yellow onion, thinly-sliced
  • 3 1/2 teaspoons olive oil, divided
  • 1 teaspoon granulated sugar
  • 1/4 teaspoon salt
  • 1-2 tablespoons water
  • 1 teaspoon dried rosemary
  • 1 garlic clove, thinly sliced
  • 5-ounces sliced shiitake mushrooms
  • 4 ounces swiss cheese, shredded
  • 2 whole wheat tortillas
  • Olive oil or cooking spray
  • Greek yogurt or sour cream, for topping


  1. For the onions: Heat 1 teaspoon of olive oil in a large skillet. Add the onions and cook for 10 minutes over medium-low heat, stirring occasionally. After 10 minutes sprinkle in the sugar and half the salt. Continue to cook for another 30-35 minutes, stirring occasionally and adding oil if the onions begin to stick. You can also add an additional 1/2 teaspoon of olive oil and a bit of water if the onions look too dry.
  2. Preheat oven to 325 degrees. Combine the mushrooms, 2 teaspoons olive oil, remaining salt, and rosemary. Transfer to a foil-lined baking sheet. Roast for 15 minutes, remove from oven and stir, then roast for another 15 minutes.
  3. To assemble the quesadillas, cover half of each quesadilla with 1/4 of the cheese, 1/2 the mushrooms, 1/2 the onions, and another 1/4 of cheese. Fold the tortilla over itself and press down.
  4. Coat a large non-stick skillet with cooking spray, and cook the quesadillas over medium heat. Flip once the tortilla is golden and the cheese is melty, about 3 minutes, and cook on the other side until golden. Let sit for 2-3 minutes before cutting.


4 Responses to “Roasted Mushroom & Caramelized Onion Quesadilla”

  1. Louise — March 10, 2014 @ 5:17 am (#)

    That looks so delicious I want to go out and buy ALL the ingredients now and make it for my lunch. And I am still full up from breakfast. My gamut of feelings tends to encompass what am I going to eat next to what am I going to wear next? As shallow as a white bread roll me.

  2. Katrina @ Warm Vanilla Sugar — March 10, 2014 @ 7:38 am (#)

    Me and this quesadilla foreveeeeer!! Yum!

  3. cheri — March 10, 2014 @ 9:45 am (#)

    This quesadilla looks amazing! Love all the ingredients you used.

  4. Cindy — May 15, 2014 @ 10:41 pm (#)

    Well Katie your story was funny and I needed a laugh, so thanks. Your recipe looks delicious and I can’t wait to try it! Mushrooms, cheese and onions you can’t go wrong with that!