Fresh Green Bean Casserole

This easy recipe for fresh Green Bean Casserole is our take on the classic Thanksgiving side dish made from scratch. Make this rich casserole with a homemade crunchy onion topping that is hearty and comforting for any holiday or weeknight dinner. 

fresh green bean casserole with onion strings in a white rectangular casserole dish

When it comes to Thanksgiving or any holiday meal, the classic dishes are the best. Fresh green bean casserole is a staple on the Thanksgiving table. The balance of creamy and crunchy is a perfect pairing to the flavors of fresh green beans and hearty mushrooms.

Although the recipe is made from scratch, it comes together relatively easily. We use fresh green beans that are cooked in a flash. The tender green beans are then tossed with a homemade mushroom sauce that tastes better than canned mushroom soup and contains all-natural ingredients. 

Before baking a simple onion topping gets layered on the top giving it a toasted onion taste with a crunchy texture that ties in all of the ingredients perfectly. 

This side dish tastes great for a weeknight dinner or for the holidays. Serve this casserole on Thanksgiving with whole roasted turkey, turkey tenderloin, twice baked mashed potatoes, apple cranberry sauce and sautéed butternut squash.

Why You’ll Love This Recipe

  • This green bean casserole without mushroom soup uses a homemade mushroom sauce that has a fresh flavor and is made with natural ingredients. 
  • The crunchy onion topping is homemade and gives the dish a great texture and onion flavor.
  • You can serve it as Thanksgiving green bean casserole or use it as a side dish throughout the year with your favorite protein. 

You can cut the prep time down to 15 minutes and the cook time down to 25 minutes if you prep the onions in advance or use premade crispy fried onions.

Green Bean Casserole Ingredients

Mushroom Sauce & Green Bean Base

  • Fresh Green Beans – You’ll need trimmed & halved green beans to make up the base of this dish. 
  • Butter – Used to cook down the mushrooms and to help create a creamy mushroom sauce. 
  • Cremini Mushrooms – These add an delicious flavor to the sauce that is hearty and fresh. Any small brown mushrooms will work.
  • Fresh Garlic – Infuses the dish with fresh garlic flavor. 
  • All-Purpose Flour – Helps thicken up the sauce. You can substitute with a gluten free 1:1 all purpose flour to make it gluten free.
  • Heavy Cream – Adds a rich creamy texture to the base of the sauce. You can substitute with half and half, if needed.
  • Italian Seasoning – A mixture of Italian herbs properly flavors the mushroom sauce.
  • Seasonings – A mix of salt, pepper, and nutmeg helps balance the flavors in the sauce. 
  • Parmesan Cheese – Adds a layer of salty cheese flavor that pairs well with green beans. Freshly grated Parmesan is best.

Onion Topping

  • Onion – Freshly sliced onions add a rich onion flavor that gets better as it bakes. 
  • Buttermilk – Helps tenderize the onion preparing it for baking. You will dredge the onions in the milk before coating in flour.
  • All Purpose Flour – Helps make the onions nice and crispy. You can substitute with a gluten free 1:1 all purpose flour to make it gluten free.
  • Salt & Pepper – Enhances and balances the flavor of the onions when baked. 

While the homemade onion topping is a highlight of this dish, you can use premade crispy fried onions to save time. Simply skip the step to make fried onions.

mixing together ingredients for the onions

How to Make Fresh Green Bean Casserole

Onion Topping

  1. Prepare for baking: Preheat the oven to 400 Fahrenheit. Line a baking sheet with parchment paper then set aside. 
  2. Soak the onions: Add the sliced onions to a medium bowl along with buttermilk making sure they are fully covered. Let them soak for 15 minutes, then drain. Discard any leftover buttermilk. 
  3. Season the onions: Add the soaked and drained onions to the bowl, then coat them with flour, salt, and pepper. Toss to evenly distribute. 
  4. Bake the onion topping: Add the seasoned onions onto a baking sheet, then spray them with cooking oil spray until well coated. Bake the onions for 25-30 minutes making sure to toss at least once or twice.
mixing together ingredients for the mushroom sauce

Mushroom Sauce & Green Bean Base

  1. Cook the green beans: Bring a large pot of water to a rolling boil. Add in the prepared green beans and cook them for 7 to 9 minutes or until they are bright green and tender. Drain them in a colander and set them aside while the mushroom sauce is made. 
  2. Cook the mushrooms and garlic: Add butter to a large skillet and melt over medium heat. Add the sliced mushrooms and saute for 6 to 8 minutes stirring often until they are fully cooked and golden brown. Add in the garlic and cook for an additional 2 minutes. 
  3. Thicken and season the mushroom sauce: To the pan with mushrooms, sprinkle the flour over top and cook it into the mushroom mix for 2 minutes. Then add in the cream, Italian seasoning, salt, pepper, and nutmeg and whisk until fully combined. Cook until thickened for about 5 minutes. Remove from heat and adjust seasonings if necessary. 
  4. Assemble and bake: Add the prepared green beans to a bowl with the parmesan and toss until combined, then pour the homemade mushroom sauce on top and toss until fully coated. Add the mixture to a casserole dish, then evenly distribute the onion topping on the top. Bake for 20-25 minutes or until sauce is bubbling and the onions are golden brown. Let cool for 10 minutes before serving. 
mixing green beans with sauce and pouring into casserole

Expert Tips

  1. Green beans should be fresh and crisp. When choosing green beans, make sure they are a fresh green color with no bruising or marks on the outside. They should be freshly crisp and taste slightly sweet raw. 
  2. Cut green beans into bite sized pieces. After trimming the stems of the green beans, cut them into bite-sized pieces for the fresh green bean casserole. If you have longer green beans, you may need to cut them in thirds or fourths. 
  3. Sift the all-purpose flour before adding it to the mushroom mix to prevent any lumps in the homemade mushroom gravy. 
  4. Allow the casserole to cool for 10 minutes after removing it from the oven. This will help naturally thicken the mushroom sauce. 
  5. Do not skip the step of soaking the onions in buttermilk. This helps to tenderize the onion and helps the seasoning stick to create a crispy texture on the outside. 


Store leftovers in an airtight container in the fridge for up to 3 days. Reheat in the microwave or in the oven.

Make Ahead: Prep this casserole in a baking dish the day before, but store the onion topping separately in a sealed container. Cover the casserole and store in the refrigerator. When you’re ready, all the onions just prior to baking.


  • Use your favorite mushrooms. We used cremini mushrooms in this recipe, but feel free to use any type of mushroom you enjoy including button, shiitake, or portobello mushrooms. 
  • Substitute with canned green beans. Fresh is always best, but if you’re short on time or you can’t find fresh green beans you can use canned green beans in this recipe. Just make sure they are fully drained and rinsed as they usually contain salt. 
  • Use frozen green beans. Frozen green beans can also be used to make this fresh green bean casserole. Just make sure they are fully thawed and that any excess liquid is drained out. 
  • You can skip the onion topping and add crumbled ritz crackers, saltines, or panko breadcrumbs that have been tossed in melted butter to spread on top before baking. You can also use pre-made crispy french fried onions topping instead of the homemade topping.
  • Add some extra flavor to this Thanksgiving side dish by sprinkling the top with chopped bacon, grated cheese, or slivered almonds for crunch. 
baked green bean casserole in a white casserole dish

Other Thanksgiving Side Dish Recipes

Try any of our favorite side dishes on your Thanksgiving menu!

Did you try this Fresh Green Bean Casserole? Leave a recipe rating and review below.

fresh green bean casserole with onion strings in a white rectangular casserole dish

Fresh Green Bean Casserole

Yield: 8 servings
Prep Time: 20 minutes
Cook Time: 50 minutes
Total Time: 1 hour 10 minutes
A classic side dish made with fresh green beans and homemade mushroom sauce and onion topping.
5 from 2 votes


Onion Topping

  • 1 medium onion, halved and sliced
  • 1 cup buttermilk
  • 1/3 cup all-purpose flour
  • 1/4 teaspoon kosher salt
  • 1/4 teaspoon black pepper
  • Olive oil cooking spray

Mushroom Sauce

  • 2 pounds green beans, trimmed and halved into smaller pieces
  • 3 tablespoons butter
  • 8 ounces cremini mushrooms, quartered
  • 4 cloves garlic, minced
  • 2 tablespoon all-purpose flour
  • 2 cups heavy cream
  • 1 1/2 teaspoons Italian seasoning
  • 1/2 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 1/4 teaspoon ground nutmeg
  • 1/4 cup fresh Parmesan cheese, grated


  • Preheat the oven to 400 degrees F. Line a large baking sheet with parchment paper and set aside.
  • Combine onions and buttermilk in a medium bowl. Let soak for 15 minutes, then drain and discard the buttermilk.
  • Return the drained onions to the bowl. Sprinkle them with flour, season with salt and pepper, and toss to coat.
  • Transfer the onions to the prepared baking sheet. Coat them generously with cooking oil spray.
  • Bake for 25-30 minutes, tossing once or twice, until tender and crisp. Set aside to cool slightly. Reduce the oven temperature to 375 degrees F.

Mushroom Sauce

  • While the onions are baking, make the casserole. Bring a large pot of water to boil. Cook green beans for 7-9minutes, until tender. Immediately drain the beans into a colander and set aside.
  • In a skillet set over medium heat, melt the butter.
  • Add the mushrooms and cook for 6-8 minutes, stirring occasionally, until golden brown and reduced in size. Add the garlic and cook for another 2 minutes.
  • Sprinkle the flour over the mushrooms, stir, and cook for 2 minutes. Stir the heavy cream, Italian seasoning, salt, pepper, and nutmeg into the skillet and whisk well to combine. Continue cooking for about 5 minutes, until thickened. Remove from the heat, taste, and season with more salt and pepper, if desired.
  • Transfer the green beans to a large bowl and toss with the Parmesan. Pour the mushroom sauce over the beans and toss to coat.
  • Transfer the beans to the casserole dish and evenly distribute the onion topping over the top. Bake for 20-25 minutes, until the onions are golden and the sauce is bubbly.


Storing: Any leftover casserole can be stored in an airtight container in the fridge for 3-4 days. 
Freezing: The best way to freeze fresh green bean casserole is uncooked and without the onion topping. Prepare the mushroom sauce and the green beans and place in a casserole dish. Tightly wrap the dish with plastic wrap, and then a layer of aluminum foil. Freeze for up to 6 months. 
Reheating: To cook the frozen uncooked casserole, preheat the oven to 350F and cook for 45-60 minutes or until the casserole is warm through the center. Add the onion topping and bake for an additional 15 minutes or until the onion top is golden brown. 


Calories: 350kcal, Carbohydrates: 20g, Protein: 7g, Fat: 28g, Saturated Fat: 18g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 8g, Trans Fat: 1g, Cholesterol: 98mg, Sodium: 369mg, Potassium: 497mg, Fiber: 4g, Sugar: 6g, Vitamin A: 1870IU, Vitamin C: 16mg, Calcium: 173mg, Iron: 2mg
Course: Side Dish
Cuisine: American
Author: Ashley C.
If you try this recipe, don’t forget to leave a review below or share a photo and tag @spoonfulofflavor on Instagram.

2 comments on “Fresh Green Bean Casserole”

  1. I’ve never made a proper green bean casserole but this year is going to be it! Loving this nostalgic recipe but with all real-food ingredients (aka no canned cream soups involved!).

  2. Oh, I love green bean casserole! I’ve never tried to make my own crispy onions. I’m going to make this tomorrow!!

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