Caramelized Leek, Fennel & Onion Gratin (Vegan - Paleo)

Dairy FreeKetoPaleoSpecific Carbohydrate DietVeganWhole30

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This Caramelized Leek, Onion & Fennel Gratin is an easy one pan side dish that is creamy and so delicious. It’s a great Vegan and Whole30 gratin to serve at your next family meal, everyone will love it without realizing it’s dairy free.

Let’s be honest, when it comes to side dishes gratin has got to be high up on most people’s list. A creamy sauce, tender vegetables and a crunchy top, it’s just too good to resist.

Unfortunately if you are on a Dairy Free or Paleo diet, gratin which is usually packed with cream, cheese and butter, is strictly off limits.

Enter this decadently rich and creamy Vegan and Whole30 gratin that tastes like it is packed with dairy! Plus by swapping potatoes for leeks, fennel and onions, the dish has a delicious caramelized flavour.

I originally tried making this Leek, Onion & Fennel Gratin with coconut cream, but really struggled to mask the sweet coconut flavour which overpowered the dish, so I switched to my favourite vegan cream substitute, cashews. The sauce is so creamy and delicious that you would never know it doesn’t actually contain any dairy. Just make sure that you use a high speed blender or NutriBullet so that the cashews completely break down and there are no little bits remaining.

Although you could put the vegetables in raw and let them bake in the sauce in the oven, I love the caramelized flavour they develop when first cooked on the stove top. I find that this also makes the dish quicker to prepare and removes any of the uncertainty of whether the vegetables are fully cooked through after baking.

I think this vegan gratin would be a fantastic addition to any Thanksgiving dinner. You could prepare this dish up to 2 days in advance by sautéing the vegetables and making the cashew cream and then simply combine them together and bake the day of.

Here are a few other side dishes that you might enjoy:

THE BEST Cauliflower Mash
Roasted Radishes
Asian Brussels Sprouts

If you make this recipe let me know in the comment section below, I would love to hear what you think or take a photo and tag me (@everylastbite_) on Instagram, I love seeing your photos!

Caramelized Fennel, Leek & Onion Gratin

Every Last Bite

This Caramelized Leek, Onion & Fennel Gratin is an easy one pan side dish that is creamy and so delicious. It's a great Vegan and Whole30 gratin to serve at your next family meal, everyone will love it without realizing its dairy free.

4.41 from 25 votes

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Ingredients

2 tbsp olive oil/coconut oil
3 leeks thinly sliced
2 white onions thinly sliced
2 small fennel thinly sliced
2 cloves garlic crushed
1/4 tsp salt
1/2 cup cashews soaked in boiling water for 10 minutes
3/4 cup almond milk
1 tbsp dijon mustard
1/2 tsp pepper
2 tbsp nutritional yeast (sub for 1/4 cup parmesan if on SCD)
1 cup vegetable/chicken stock
1 tsp fresh thyme

Instructions

Preheat the oven to 175 degrees Celsius (350 degrees Fahrenheit)
In a high speed blender add the drained cashews and almond milk and blend until completely smooth. Pour the mixture into a pot and add in the mustard, pepper, nutritional yeast (or parmesan) and stock. Leave to simmer for 5 minutes or so until the liquid begins to thicken. It should coat the back of a spoon. Stir in 1 tsp fresh thyme
In a cast iron skillet heat the oil on medium heat and then add in the leeks, onion, fennel and garlic. Sprinkle with salt and leave to cook for 10 minutes, until they become soft, slightly caramelized and golden in colour.
Pour the cashew cream into the skillet and stir through so that it coats all of the vegetables. Transfer the skillet to the oven and bake for 20 minutes until bubbly and golden on top.
Before serving sprinkle with fresh chopped parsley or thyme.

Nutrition

Calories: 186kcalCarbohydrates: 18gProtein: 6gFat: 7gSodium: 375mgPotassium: 578mgFiber: 5gSugar: 4gCalcium: 116mgIron: 2mg

Tried this recipe?Leave a comment below and let us know how it was!

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38 comments on “Caramelized Leek, Fennel & Onion Gratin”

Jordan — February 14, 2024 @ 9:26 pm Reply

The flavor of this recipe is on point! It gives that creamy, comforting, french style feeling of a normal butter roux. However, I ended up with WAY too many veggies -onions, leeks, and fennel -for what was needed. I used the listed ingredients in recipe (2 fennel, 2 white onion, 3 leeks). THIS WAS OVERKILL. I ended up only using half of that in the recipe and the rest I’ll use for soup later this week. Don’t know why the proportions were so off, I could barely fit half of the veggies in my regular ten inch cast iron skillet.
pavthra — June 27, 2022 @ 12:36 pm Reply

This looks like such an awesome recipe and I have everything at hand, woo hoo! Mind telling me how large your cast iron pan is? Thanks so much!
Christene — April 17, 2022 @ 4:41 pm Reply

I made this for our Easter dinner, so good!! I actually made 2 and put 1 in a pie crust turned out wonderful! Thankyou for the recipe!!
Stephanie — April 14, 2022 @ 11:37 pm Reply

Is Dijon mustard a powder form or liquid form?
Stephanie — April 14, 2022 @ 4:50 pm Reply

Is The ingredient “Dijon mustard“ a liquid version or powder? This will be my first time using any mustard in a dish!
Mary Schneider — December 22, 2021 @ 5:47 am Reply

I truly dislike these dishes which depend so heavily on tree nuts. I have a suggestion: offer those with a tree nut allergy an option. We do exist. And you have created a recipe that would kill us. If you serve this to others, please be sure to issue adequate warmings.
- Karen Noleek — September 23, 2022 @ 3:12 pm Reply
  
  Dear Mary
  I wholeheartedly agree with you. I’m allergic to leek, fennel and onions and I would also like to have an option. This recipe is life endangering!
  Maybe we can share a portion? I can have your nuts and you can have my veggies?

Caramelized Leek, Fennel & Onion Gratin (Vegan - Paleo) - Every Last Bite (2024)