This healthier green bean casserole is made from scratch without any canned soup! Made with fresh green beans and mushrooms coated in a creamy homemade white sauce and topped with the classic crispy onions, this casserole is a lightened-up and more fresh take on the traditional version.
Heat oven to 350F and prepare a large bowl of cold water with ice cubes.
For the Green Beans:
Bring a pot of generously salted water to a boil and add the green beans. Cook until bright green and halfway to tenderness, about 3 minutes. You might have to do this in batches if you do not have a large enough pot.
Immediately transfer the green beans to an ice bath and allow the beans to cool off. Drain well and trim stem ends.
For the Mushrooms:
Place a large skillet over medium-high heat and add 2 tablespoons butter and 1 tablespoon oil. Once the butter melts, add in the mushrooms. Cook mushrooms, leaving them untouched and only stirring occasionally until mushrooms are golden brown, about 20 minutes. Add another tablespoon of butter and thyme and cook for another minute. Transfer to a bowl and set aside.
For the Sauce:
In the same skillet (no need to wipe it down), melt 2 tablespoons of butter over medium-low heat. Add 2 tablespoons of all-purpose flour and cook, whisking throughout, until combined and golden brown, around 4 minutes.
Slowly add in the whole milk, whisking throughout to help them combine. Then, repeat with the broth. Increase heat and bring to a simmer, continuing to whisk often, and cook until the sauce is creamy and has thickened enough to coat the back of a spoon, about 10 minutes. If it gets too thick, add more broth.
Remove from heat and whisk the thyme, garlic powder, onion powder, parmesan, pepper, lemon zest, and lemon juice until well combined.
For the Assembly and Bake:
To a 6 qt baking dish, add the mushrooms and green beans. Pour the sauce over.
Cover tightly with foil and bake for 25 to 30 minutes. Uncover, give it a bit of a stir if desired, and continue to bake until the green bean casserole for 15 to 20 more minutes or until the top and edges are lightly browned.
Add the French’s fried onions evenly over the top and continue to bake until the onions are crispy to your liking, about 5 minutes.
Let sit for 10 minutes before serving.
Video
Notes
Have an extra ¼ to ½ cup more broth on hand in case the sauce overcooks and gets too thick.