Mushroom Onion Cheeseburger with Fries


It’s summer y’all! Grills, pools and cold lemonade. That also means veggie burgers are on the menu.

Now when it comes to veggie burgers, I like all types and variations. This is one of my favorite combos: caramelized onions, mushrooms and melted white cheese. And of course, fries. Gotta have the fries. When I was thinking about this recipe, my goal was to streamline the process so that all you need is 2 large sheet pans and an oven. I think I nailed it! Here’s how it breaks down:

  1. Bake fries.

  2. While fries are baking, prep and bake onions, and mushrooms.

  3. When mushrooms and onions are done, use the same sheet pan to heat veggie burger patties, melt cheese and toast bread.

  4. Assemble + Eat!

Basically, no time is wasted here. Lots of multitasking with big results.

Now before I tell you all the deets, I will say that you need two LARGE sheet pans. The end results will make a total of 4 veggie burgers with fries- so this is a meal! If you only have small sheet pans (or a small oven) you might wanna cut this recipe in half. Also, big thanks to Amy’s Kitchen for sponsoring this post. They’ve been feeding me veggie burgers and frozen burritos since I was a teenager!

Now let’s get cooking!


First up: crispy oven baked fries. My go-to potato is usually russet (I love their starchy texture!). For this recipe, the bigger the better. Like, find the 2 largest russet potatoes you can find. Large potatoes = larger fries = better world. Because we are baking these at a high-heat, I like to use avocado oil because it has a very high smoking point. It’s also gorgeous- I mean look at that color. Werk avocado oil (snaps fingers)!


Look at that action shot. Those fries are being tossed with loads of salt, pepper and oil! Of course, I sprinkle nutritional yeast on mine because that’s what I do. Leave it off if you don’t like it. I don’t trust anyone who doesn’t like nutritional yeast, but we don’t have to get into it.

The key here is to space the fries apart so that they have room to breath. And by ‘breath’ I mean become golden and crispy. Flipping them also is a game changer. Don’t skip that step.


Once you get the fries in the oven, you can start prepping the other ingredients. Hot tip! You can use the same bowl for tossing fries to toss the mushrooms which means less clean up. As for those stunning onions, they are drizzled with a balsamic glaze that I have, but you could just use balsamic vinegar as well. The tart acidic flavor of the vinegar along with the sweetness of the red onions caramelizes together in a very seductive way. (Too much?)


Welp, now you can see for yourself what happens to all those toppings. And they are begging to be placed on a burger. Feel free to use this onion recipe on anything! Tacos, fajitas, sandwiches, salads- they’re delightful and they keep well in the fridge.

As for the mushrooms, they’d be good with anything as well. You’ll see.


While the fries and other toppings are cooking, I like to make a big plate of my toppings. Think lettuce, tomatoes, pickles- the classics. I also like to have out vegan mayo, ketchup, mustard- and maybe an additional fun topping like sliced, creamy avocado or your favorite Sriracha? Get into it.

Sheet Pan Mushroom Onion Cheeseburger
makes 4 burgers + fries


1 extra large russet potato (approx. 1 pound)
1 ½  tablespoons avocado oil
½ teaspoon sea salt
¼ - ½ teaspoon black pepper
2 teaspoon nutritional yeast (optional)

Burgers + onions + mushrooms

8 ounces cremini mushrooms, sliced ½ inch thick
2 tablespoons avocado oil plus more for onions
2 tablespoons tamari
Few dashes liquid smoke
1 teaspoon nutritional yeast
¼ teaspoon ground sage
1 large red onion, sliced into ½ inch rounds (4 rounds total)
Drizzle of balsamic glaze or balsamic vinegar
1 box of Amy’s Organic California Veggie Burger
4 ciabatta buns and vegan butter
4 vegan cheese slices, smoked provolone or mature cheddar
Vegan mayo, ketchup and mustard, if desired
Green leaf or iceberg lettuce, hand-torn into large pieces
1 large slicing tomato, sliced into large rounds
Dill or sweet pickles (your choice!)

1. Preheat oven to 400 degrees. Scrub potato clean under running water. Slice lengthwise into ½ inch pieces. Lay each piece flat to slice lengthwise again into approximately ½ inch pieces to create long thin fries.

2. In a large bowl, toss fries together with avocado oil, sea salt, black pepper and nutritional yeast (if desired) to coat all fries with a generous coating of oil and seasoning. Gently place each fry on a parchment lined baking sheet. Line the fries in rows allowing space between each fry. Bake in the oven for 30 minutes. Remove from oven and gently turn fries over one by one. Return to oven for another 15-20 minutes until golden brown on the underside and crispy. While the fries are cooking, prepare the other ingredients and start baking them as well.

3. Using the same bowl as the fries, toss the sliced mushrooms with avocado oil, tamari, liquid smoke, nutritional yeast and sage. Transfer to a parchment lined sheet pan along with the four onion rounds. Spread everything into a single layer with a little spacing and drizzle avocado oil over each onion. Use your finger to evenly spread oil over entire surface of onion. Then, drizzle balsamic glaze and a pinch of sea salt to each round. Bake for 25 minutes.

4. Remove onions and mushrooms from sheet pan and place frozen veggie burgers on the same pan. Bake for 5 minutes. While burgers are cooking, butter the ciabatta buns. After 5, remove sheet pan from oven, flip the burger patties, and add a slice of cheese to each one. Add the ciabatta buns buttered side down onto the pan. Return to oven for 5-6 more minutes to melt cheese and toast the buns.

5. Once the cheese is melted and burgers are heated through, begin to build your veggie burgers. Spread mayo on toasted ciabatta then add lettuce, burger with melted cheese, onions, mushrooms, tomatoes, pickles and desired condiments. Of course, I don’t need to tell you how to build a burger so do what you want!


Tips, Tricks, & Other Tidbits

If preparing this for a dinner party, I suggest cooking everything right before the guests arrive so that it’s warm and ready to eat. Make sure to have a nice platter of all of the toppings and condiments ready to go with plenty of napkins!

A great dessert to serve with this would be some juicy watermelon or a fruit based sorbet. Because burgers and fries can be quite heavy, a light and refreshing dessert works beautifully.

If you like this recipe, please check out my cookbook, Mississippi Vegan.

Big thanks to Amy’s for sponsoring this blog post and recipe. If you’d to check out more recipes using Amy’s products, sign up for their newsletter here!

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