These vegan French onion burgers are made with savory caramelized onion and lentil patties, topped with an extra layer of caramelized onions and creamy herbed cashew cheese.

I realized after making these that I have a thing for turning non-burger foods into veggie burgers. Check it out: meatloaf, Reuben sandwich, falafel, nachos...
I didn't actually go into this one intending to turn French onion soup into a burger — it was more of a loose idea to put caramelized onions into a burger. Once I got rolling though I realized it had to be French onion soup, because duh, French onion soup is fantastic.
It's also something that I really miss from time to time, and as my husband and I discovered while chatting one day, lots of new vegetarians are apt to eat by mistake before realizing it's totally not vegetarian. So I think lots of us probably have a good deal of attachment to French onion soup. It's obviously not vegan, so no more goofing up in that department.
So maybe some day I'll make a vegan French onion soup that's actually a soup, but for now...burgers!
Lentil patties seemed appropriate, so I went with that and added some savory seasonings.
Then I topped everything with a creamy herbed cashew cheese. You could use some homemade or store-bought vegan mozzarella if you're a real stickler when it comes to French onion soup-themed things, but honestly, the spreadable cheese is delicious and it really does taste French onioney when paired up with the burger and caramelized onions, so you should make it.
My only regret was going with regular old burger buns. How perfect and delicious would these have been on crusty French rolls? Kind of like the croutons in French onion soup, right? But by the time I figured that out I'd photographed and devoured my burgers, so too late. But maybe some nice person will try out the crusty bread variation and let me know how great it is. :)
Vegan French Onion Burgers with Herbed Cashew Cheese
Ingredients
For the Patties and Caramelized Onion Topping
- 2 tablespoons olive oil plus a little extra for grilling the patties
- 1 ½ pounds yellow onions about 3 medium, sliced thin
- 3 garlic cloves minced
- 1 ¼ cup rolled oats
- 2 cups cooked brown lentils see note
- ½ cup chopped walnuts
- 2 tablespoons chopped fresh parsley
- 1 tablespoon fresh thyme leaves
- 2 tablespoons soy sauce
- 1 tablespoon vegan Worcestershire sauce
- ½ teaspoon black pepper
For the Herbed Cashew Cheese
- 1 cup raw cashews soaked in water 4-8 hours, drained and rinsed
- 1 tablespoon red wine vinegar
- 1 garlic clove minced
- ¼ cup unflavored unsweetened soy or almond milk
- ½ teaspoon salt
- ¼ cup chopped fresh parsley
- 2 tablespoons fresh thyme leaves
- 2 tablespoons chopped fresh chives
For Serving
- 4-6 burger buns or crusty French rolls
- Lettuce tomato, and any other burger toppings of your choice
Instructions
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Coat the bottom of a large skillet with olive oil and place it over medium-low heat. Add the onion and stir a few times to coat with the oil. Allow to cook for 45 minutes to 1 hour, stirring occasionally, until the onions are browned and caramelized. Stir in the garlic, raise heat to medium, and cook for another minute, until very fragrant. Remove from heat and transfer the onions to a plate.
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Place the oats into the bowl of a food processor and blend to a flour. Add in the lentils, walnuts, parsley, thyme, soy sauce, Worcestershire sauce, black pepper, and about â…” of the caramelized onions. Pulse until the ingredients are well mixed, being careful not to overdo it. Taste-test and adjust the seasonings to your liking.
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Make the cashew cheese by placing the cashews, garlic, red wine vinegar, milk, and salt into the bowl of a food processor and blending until smooth. Add in the herbs and pulse a few times until finely chopped and well mixed. Scoop the mixture into a bowl.
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To make the burgers, shape the lentil mixture into 4 to 6 patties. Add a touch more oil to the skillet you used for the onions and place it over medium heat. When the oil is hot, add the patties and cook for about 4 minutes on each side, until browned.
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Stuff the patties into buns or rolls and top with the cashew cheese, remaining caramelized onions, and any other toppings you like. Serve.
Recipe Notes
You can use canned lentils, or cook up some dried lentils while the onions caramelize. If using dried, place ¾ cup into a saucepan and cover with about 3 cups of water. Boil until the lentils are tender, about 35 minutes, then remove from heat and drain any excess water. If you forget to soak your cashews, you can just boil them in water for about 15 minutes.
I'm so glad to see more gluten free recipes! I am vegan, but I also am allergic to dairy and eggs, plus I'm gluten sensitive. Thank you for all you yummy recipes!
Thank you! I'm glad you're enjoying them. :)
I can not wait to try this burger, it sound delicious! Miam!
Thanks! I hope you enjoy it!!
Those burgers look and sound so delish. I love cashew cream sauces too.
Thank you! :)
In the herbed cashew cheese recipe, I am confused with the two additions of fresh thyme.. Recipe calls for 2 T fresh thyme leaves, and 2 T chopped fresh thyme?? Is this correct? Why two different additions of fresh thyme? Please clarify
Thank you for catching that! The second one is supposed to be chives! Fixed it!
Wow, this vegan burger looks so delicious! I'm definitely going to try it myself =)
Thanks so much! I hope you enjoy it!!
WOW! I made this and it is absolutely spectacular! I can hardly wait to make it again! I had some left and instead of letting it die in the fridge, I froze it for another day. I'm hoping that's okay...time will tell (unless you tell us before hand!). One reason I had to stop eating it is I had a tooth pulled and couldn't get anything in the whole that was left. Hopefully, soon all that will be resolved and out of the freezer it will come. YUM!
As always Ailssa, you struck gold again. Thank you for making so many incredible dishes for all of us. PS I give it 5 stars!
Marcia
I'm so glad you enjoyed them! And I think they should be fine in the freezer. :) And sorry about your tooth - I hope you feel better soon!
Does it matter if the lentils are green or red?? I have all colors of lentils but no brown!?! Go figure.
I think green will work. :)
So I want to make these but is there something that you would suggest to replace the oats? My boyfriend is allergic but we both love French onion soup and these sound so good!
I think panko breadcrumbs would work! Please let me know how they turn out if you try it!
Hi Alissa...I am very interested in making these and freezing them. Have you tried freezing any of your burger recipes and if so how did they come out?
Thanks so much,
Alissa
Ps....I spelled my own name wrong! its Alissa :)
Lol. I do it all the time too. :)
Most veggie burgers freeze just fine and I think these would too - even the cheese! You can go through the entire process of making them and then freeze, but what I really like to do is mix everything in the food processor, then seal the mix up and freeze it. Then when you're ready, just thaw, shape the patties and cook - it's just like they're freshly made.
Hi! I just found this recipe and would love to make it but I’m allergic to lentils-can they be substituted with something else to make the burgers?🤞
Can you have chickpeas? I think they'd work well!
This was incredible! Due to user error, I've never been successful with veggie burgers, but the mixture was blended so perfectly that they kept their shape the whole time. The flavour was amazing.