This green bean casserole recipe is made with a simple homemade sourdough white sauce and topped with crispy, sourdough French-fried onions. Unlike the traditional green bean casserole, this one doesn't have cream of mushroom soup in it, making it healthy, fresh, and flavorful. The creamy sauce with a sourdough tang, tender green beans, and crispy sourdough onions all come together to make an irresistible dish for your holiday table.
In a small saucepan, heat 2-3" of melted beef tallow or oil over medium heat.
In a small bowl, mix sourdough discard and seasonings.
Add thinly sliced onions and toss to coat.
Fry in small batches in the oil. Don’t add too many at once because the steam from the onions cooking can overflow the pot.
Flip once during cooking and cook until golden brown.
Remove from the oil using a slotted spoon and place on a plate to cool.
Make the green bean dish:
In a 12" cast iron skillet, saute diced onions and garlic in butter until soft.
Add sourdough discard and stir.
Add broth, milk, salt, and pepper and cook until thick.
Add green beans and heat through.
Crumble up the french onions and stir some into the green beans and place the rest on top of the casserole.
Bake at 350 degrees for 15-20 minutes.
Notes
I always use my home-canned green beans for this casserole, but you can use fresh green beans as well. You'll want to blanch the green beans to soften them a bit if they are fresh.Use any leftover onion pieces you may have in your refrigerator to make the french onions. Just dip them in a little bit of sourdough discard and fry in some melted beef tallow or oil.I suggest making the homemade creamy sauce first in a large pan, and then adding the green beans to it. This will save you from making extra dishes.You can also add fresh mushrooms to the white sauce along with the sauteed onions and garlic, to make a creamy mushroom sauce.You can make this casserole ahead of time but leave the french onions off until just before serving so they maintain their crispy texture.If you don't want to make your own crispy fried onions, you can always buy french fried onions from the store.