Let me preface this whole post by saying I don’t think I have ever had the green bean casserole with the canned green beans and cream of mushroom soup. I have definitely had those french fried onions (#latenightsnacking).
I’ve made homemade green casserole before on the blog, but I was never completely satisfied by it. One of the hardest things when first cooking what how to get sauces to thicken with a roux. I swear that I would follow recipe directly exactly but it would never thicken up as promised (I am looking at you chicken pot pie recipes…).
BUT I was determined. And I wanted to make a casserole completely from scratch to see if I could get those french fried onions to be even better than than those boxed ones.
And finally I feel like I was able to master a homemade version of cream of mushroom! Forgive the darker photo from a winter evening and make this homemade this holiday season!
For the Casserole:
1 lb green beans, trimmed and chopped
1 lb cremini mushrooms, chopped
Salt and pepper
3 tablespoons butter
3 cloves garlic, minced
3 tablespoons flour
3/4 cup chicken stock
3/4 cup half and half
For the onions:
1 onion, thinly sliced
2 cups buttermilk
2 cups flour
1 tablespoon salt
1 teaspoon pepper
1 teaspoon cayenne
Oil for frying
Cover sliced onions with buttermilk and refrigerate for an hour.
Heat large pan and add green beans. Cook for 2-3 minutes until sizzling. Add water until beans are just covered and cook for 4-5 minutes until crisp-tender. Drain green beans and cool with cold water (or do water bath if you aren’t feeling as lazy as I was when cooking).
Heat large pan and add butter and mushrooms. Season with salta and pepper and cook until mushrooms have released water, about 6-8 minutes. Add garlic and cook until fragrant, about 1-2 minutes. Stir in flour and cook for 1-2 minutes. Slowly stir in chicken stock and half and half. Bring to boil and reduce to simmer while stirring. Simmer until thicken for about 15-20 minutes. Remove from heat and transfer into 8×8 casserole dish (or 9×9 if you want a smaller filling to fried onion ratio.)
Preheat oven to 425°F. Heat oil to 375°F.
In large dish, mix flour, salt, pepper, and cayenne. Working in batches, drain onions and dip into flour mixture, coating to cover. Fry in oil for 1-3 minutes, until golden brown. Transfer to paper towels to drain and salt when hot out of the oil. Repeat with remaining batches.
Sprinkle onions on top of casserole. Bake in oven for 15-20 minutes, until bubbling and onions are golden brown.