Mushroom-Basil Au Gratin

This dish is based on traditional au gratin potatoes, but without the cheese, milk, butter and flour. Along with the potatoes, thin layers of mushroom and onion are stacked with fresh chard and basil. A few cashews make the sauce rich and creamy.

4-5 large Yukon potatoes, sliced thinly
8 large white or crimini mushrooms, sliced thinly
1 yellow onion, sliced thinly
1 bunch chard
½ bunch fresh basil (about 20 leaves)

1/3 cup raw cashews
1 cup water
½ cup soy milk
½ cup parsley leaves
2 green onions, diced
½ teaspoon garlic powder

1. In a high-speed blender, grind the cashews by themselves first until fine; add the water, soy milk, parsley, green onions and garlic powder, and blend thoroughly. Set aside.

2. To prepare the vegetables, using a mandolin slicer with the thin slicing blade (as if you were making potato chips), slice the potatoes, mushrooms and onion, and set aside in separate bowls. Remove the thickest stems from the chard leaves, and remove the leaves of basil from their stems; wash both and set aside.

3. In a 13″x9″ rectangular glass baking dish, layer vegetables in this order, starting with a thin layer of sauce in the bottom of the dish (you do not need to oil the pan): potatoes, mushrooms, onions, basil, chard, sauce. Add a second layer of vegetables and sauce, then finish with a final layer of potatoes, pouring the last bit of sauce over the top of them. Cover with aluminum foil and bake at 400 degrees for 35 minutes. Remove the foil and cook an additional 15 minutes until lightly browned on top (optional: grind some cashews on top first). Remove and let sit for at least 5 minutes before serving.

Assembling the veggies

Preparation: 30 minutes; cooking time: 50 minutes; serves: 6-8

Notes: Don’t be afraid to pile the vegetables high when making your layers, as everything will condense down quite a bit while cooking. / If you don’t have a high-speed blender (like a Vitamix or Tribest personal blender), you may use a standard blender; just soak the cashews in the 1 cup of water for about 15 minutes first. If there are small cashew pieces in your sauce still, no worries, it will still work fine. / For a lower fat dish, leave the cashews off and decrease the water by ½ cup. The layers will not stick together as well, but the flavor will still be great. / If you do not have a mandolin, just slice the vegetables by hand as thinly as you can. / This dish is great for leftovers.

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  1. Renee says

    This looks so yummy, but I’m having trouble finding the ingredients now, in March. might you have variation suggestions for the Winter/Spring season?

    • Linda Dale says

      I’ve never had any trouble finding fresh basil. Even regular supermarkets normally have it all year around in those small plastic clamshell containers. And, if you can’t find chard, you could substitute fresh spinach.

  2. says

    Hi Renee, you might try Whole Foods; they usually have basil, but it may cost a bit more. Otherwise, you can use another fresh herb (tarragon, parsley, cilantro) but I don’t think it would have that same zip as the basil brings. Same with the chard; can be found at Whole Foods. Hope that helps :)

  3. Linda Dale says

    This dish looks divine and I think my daughter’s kids (both little, tiny vegans) would love it. Can’t wait to make it. :-)

  4. Saffron says

    Delish!! The third batch in as many days is now in the oven. It’s so easy to make with my new Tribest blender and mandoline! I keep forgetting to get mushrooms, though. I’ve made it with yukon gold potatoes, sweet potatoes, and now with yams. Tomorrow I think I’ll try a new recipe.:)

  5. Lynn says

    I made this for my condo’s potluck Holiday (Christmas) Party today, and it was very popular. Through long experience, I have learned not to label anything as “vegan “. Just put it out there and let people enjoy.

    This was one of the first dishes used up even though most people here are fond of meat. Maybe a meat and potatoes thing, and I supplied the potatoes?

    Anyway, thank you very much forthis recipe!

  6. Sandy says

    This is one of my all time favorites – especially for company or groups. I think this recipe might be the nudge to get me to buy a madolin slicer! Thank you – YUMMM.

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