Green Beans with Mushrooms in Mustard Sauce {Maille Mustard Recipe}


I have fond memories of my grandmother's green bean casserole served during Thanksgiving dinner, quite possibly because in addition to the creamy mushroom soup base, there was a layer of Swiss cheese within the dense bed of green beans. The classic version has the green beans swimming in cream of mushroom soup-as-béchamel sauce and topped with fried onions. That recipe will stay put in our family cookbook, as this version of haricot verts is brought into the holiday spotlight, dressed up in a sensuous mustard sauce.

I think it's necessary to keep the crisp crunch and bright green color of the beans. Tossed lightly in a mustard sauce, the taste is even more heavenly with earthy wild mushrooms and Maille's Truffle and Cep Mushroom flavored mustard, just to make sure your guests savor every serving spoonful of it. Your vegan guests will be pleased to have something other than sweet potatoes on the table as a vegetarian side, while those who like everything on the table will have to share this.

Nothing complicated or laborious is required, simply prep ahead and assemble before serving. It is also quite fine to serve this room temperature, as the essence of the truffle mustard mingling with the mushrooms creates more depth of flavor. You may not need to worry about leftovers on this one, as it pairs well with mashed potatoes, celery root purée, and all the other dishes for your holiday feast.


Using Maille's Truffle and Cep Mustard as a finishing sauce, these green beans will shine during your holiday feast. A classic dish becomes a heavenly treasure with the woodsy notes of black truffles and mushrooms. To keep this recipe vegan, use vegan butter, but of course, if vegetarian, the best quality European butter works beautifully to enhance this luscious mustard sauce.

Serves: 4-6


  • 1 ½ pound green beans, rinsed, trimmed and cut in half

  • 2 tbl olive oil

  • 2 tbl vegan butter

  • dash of sherry

  • 8 shallots, minced (1/2 for crispy topping)

  • 6 cloves garlic, minced

  • 1 cup chopped mushrooms (chanterelles, baby bellas, morels and/or cremini)

  • 3/4 cup mushroom broth

  • 2 tbl Maille Truffle & Cep mustard

  • 2 tbl Maille Dijon mustard

  • white/black truffle sea salt and ground black pepper


Blanch the green beans:

Bring a large pot of water to a boil with sea salt. Add green beans and cook for 5 minutes, then drain and place in an ice water bath to stop cooking. Drain and set aside.

Prepare the crispy shallots:

Put olive oil in a small saucepan. Add 4 minced shallots and cook on medium heat, stirring occasionally, about 12-14 minutes until golden brown. Turn down the heat if they get too dark and crispy.

Transfer shallots to sieve over a bowl and let them drain well, then blot the shallots by laying them upon a paper towel. They will become crisp as they cool. Sprinkle lightly with sea salt. You can save the shallot oil in a separate jar for cooking the sauce.

Prepare the sauce:

In a large skillet over medium heat, add the shallot-infused olive oil, vegan butter, half the amount of shallots (4 remaining) and garlic. Cook for 2-3 minutes, then add mushrooms and season with a little sea salt—if you have white or black truffle sea salt, this makes a good use for it, but use sparingly. Cook for 3-4 minutes more or until lightly browned. Splash in a little sherry before turning off the flame.

Turn off heat and add four tablespoons of Maille mustard. Incorporate well, as the broth, sherry and reduced liquid of the mushrooms will allow the mustard to coat the green beans evenly.

Add 1/2 cup of the fried shallots and all of the cooked green beans. Toss to coat well, top with remaining fried shallots and transfer to a serving platter.

Serve and enjoy. Bon appetit!


To find Maille mustards, go to Maille's website to shop the exclusive selections. Maille makes the perfect gift for gourmets during the holiday season. Personally Maille mustard is my favorite mustard brand. This post is not a paid for sponsorship, but a happy match between Maille mustard and I, as they do send jars of mustard for my recipe testing (yet I also buy more myself-- I'm addicted). Please try them! The holiday selections are gorgeous, as any mustard lover would swoon over these jars. (All food photography and styling is my own.)