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Green Bean Mushroom Gratin

Updated On: Jan 08, 2024

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Does your Thanksgiving table include fresh green beans? If so, add this easy recipe for Green Bean Mushroom Gratin to the list (aka cheesy green bean casserole). The recipe below can be modified to feed a few or a crowd easily. By the way, this delicious green bean casserole recipe is not just for Thanksgiving , you can make it year round and it’s even great on the BBQ or Smoker! Delish!

green bean casserole with mushrooms, cheese and crispy onions

Oh the Thanksgiving sides – how do I love thee. Seriously, I’d be down for a holiday dinner that was turkey-free and just loaded with yummy Thanksgiving side dishes like this Green Bean Mushroom Gratin, Creamy Mashed Potatoes, Stuffing, Classic Cranberry Sauce, and all the Rolls.

Is it just me? Ok fine, Turkey is great too. I made this Rosemary Dijon Roast Turkey recipe for Spiceology a couple years ago for Thanksgiving dinner and it was outrageously good. Juicy and soooo flavorful. This year I created 3 different versions: Clementine Turkey Rub, Honey Glazed Nashville Hot, and Lemon Pepper that we tested on turkey legs and it was very hard to pick a fave. They were each unique and flavorful. Check out the recipes on Spiceology

3 different ways to make Thanksgiving Turkey

Ingredients in Green Bean Gratin

This recipe for Green Bean & Mushroom Gratin only requires a few fresh ingredients. You can parboil the green beans the day before and refrigerate but this recipe will be best made right before you’re going to bake it. Make your Thanksgiving day easy by making a quick and fresh version of the classic green bean casserole.

green bean & mushroom gratin casserole
  • Green Beans or Haricot Vert – I like using haricot vert because they are smaller more tender green beans and work well for a quick cook.
  • Fresh Mushrooms – updated from the traditional canned cream of mushroom soup version, I use fresh mushrooms like crimini or baby bella mushrooms or white mushrooms that are quartered or halved, depending on size.
  • Heavy Cream – makes for a creamy mushroom sauce
  • Fresh Garlic – you could use garlic powder or granules, but fresh garlic really makes for the best results.
  • Parmesan Cheese – because all things taste better with Parmesan cheese on them. Right?
  • Red Pepper Flakes, Salt & Black Pepper – add a little spice! You can omit the red pepper flakes if you don’t like a little heat
  • French Fried Onions – crispy fried onions are sprinkled on top of the casserole, but I have also been successful with panko breadcrumbs for the topping.

Find the printable recipe card with exact measurements and instructions below.

How to make Green Bean Mushroom Casserole

  1. Bring a large pot of salted water to a boil and drop in green beans for 1-2 minutes. Quickly cool them down by plunging into an ice bath. Drain well.
  2. To a casserole dish add the green beans, sliced mushrooms, garlic, chile flake, and cheese. Toss to combine.
  3. Drizzle the heavy cream over the green bean mixture.
  4. Top with French fried onions and bake for 30 minutes. Remove and devour immediately.

What is Parboiling?

Parboiling is a cooking method where you partially cook vegetables (and other foods) to a crisp tender. The vegetable should still be firm but brightly colored. Ice bath plunging will stop the cooking process to ensure the food isn’t overcooked.

simple green bean casserole side dish

Tips & Tricks

  • For storing: you may be wondering how long does green bean casserole last in the fridge. Store in an airtight container for a 3-4 days. If they last that long.
  • For reheating: Reheat green bean casserole in a microwave safe dish on 30 second intervals until warmed through, stirring occasionally.
  • For freezing: Use a freezer-safe container and freeze up to 3 months. Bring to room temperature before reheating.
  • For preparing on the grill or smoker: use a pan that is safe for the grill or smoker and prepare as directed. Grill on low for 15-20 minutes (watch to make sure it doesn’t burn) or smoke at 350ºF for 30 minutes.

Related Recipes

green bean mushroom casserole recipe

Green Bean Mushroom Gratin

A quick and easy side dish recipe for Green Bean Mushroom Gratin.
Prep Time 15 minutes
Cook Time 30 minutes
Servings 6 Servings


  • 1 lb green beans trimmed
  • 2 teaspoons olive oil
  • 12 crimini mushrooms sliced or quartered
  • 4 cloves garlic minced or pressed
  • ¼ cup Parmesan cheese
  • 1 pinch red pepper flakes
  • cup heavy cream
  • ½ cup French fried onions like French's brand
  • salt & pepper to taste


  • Preheat oven to 350ºF. Lightly coat a baking dish with olive oil. Set aside.
  • Bring a medium pot of water to a boil and lightly salt. Add the green beans and boil for 1 minute. Pull the green beans out with tongs or a spider and drop into a bowl of ice water. Allow to rest for a couple minutes. Drain well.
  • Add the green beans, mushrooms, garlic, olive oil, parmesan cheese, and red pepper flakes to the prepared baking dish and toss to combine. Drizzle with heavy cream, season with salt and pepper and top with French fried onions.
  • Bake 30 minutes. Remove and serve immediately.


Calories: 138kcalCarbohydrates: 10gProtein: 4gFat: 10gSaturated Fat: 5gPolyunsaturated Fat: 0.5gMonounsaturated Fat: 2gCholesterol: 18mgSodium: 117mgPotassium: 363mgFiber: 2gSugar: 4gVitamin A: 754IUVitamin C: 10mgCalcium: 97mgIron: 1mg
Tried this recipe? I’d love to see what you made!
Mention @farmgirlgourmet or tag #farmgirlgourmet !

Recipe By:

Heather is a recipe developer and content creator living in Vancouver, Washington. She started Farmgirl Gourmet in 2006, almost 20 years ago, as a way to share recipes with friends and family. Heather is also the co-founder of Spiceology , a unique spice company, which she started in 2013. She shares family friendly recipes for easy everyday meals with a gourmet twist.


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