01 -
First things first, get those beautiful green beans ready! Bring a large pot of salted water to a rolling boil. Drop in your trimmed fresh green beans and let them cook for about 3-5 minutes, just until they're tender-crisp and bright green. This is where I always forget to salt the water, but it makes a difference! Immediately plunge them into an ice bath to stop the cooking and preserve that vibrant color. Drain them well; nobody wants a watery casserole, right?
02 -
In a large oven-safe skillet or Dutch oven, melt 2 tablespoons of butter over medium heat. Add your sliced mushrooms and cook them until they're golden brown and all their liquid has evaporated. This can take a bit, so be patient! Then, toss in the diced onion and minced garlic. Sauté until the onion is softened and translucent, about 5 minutes. Oh, the smell at this stage is just heavenly, it's the start of something amazing for our casserole. Don't rush it.
03 -
Sprinkle the flour over the sautéed veggies, stirring constantly for about a minute. This creates a roux, thickening our sauce later. Slowly, and I mean *slowly*, whisk in the chicken or vegetable broth, making sure there are no lumps. Then, pour in the heavy cream. Keep whisking until the sauce starts to thicken and bubble gently. Season with salt and pepper to taste. Honestly, this is where the magic happens for your casserole!
04 -
Stir the blanched and drained green beans into the creamy sauce in your skillet. Make sure everything is well coated. If your skillet isn't oven-safe, transfer the mixture to a 9x13 inch baking dish. Sprinkle about half of the crispy fried onions over the top. Pop it into a preheated oven at 375°F (190°C) and bake for 15-20 minutes, until the sauce is bubbly and the casserole is heated through. I once forgot this step and just served it from the stove – still good, but not quite the same! This casserole needs that oven time.
05 -
Take the casserole out of the oven. Sprinkle the remaining crispy fried onions evenly over the top. Return it to the oven for another 5-10 minutes, or until the onions are golden brown and extra crispy. Keep an eye on them, because they can go from perfectly golden to burnt in a flash—I speak from experience! You want that irresistible crunch to finish off your casserole.
06 -
Once it’s out of the oven, let your casserole rest for about 5-10 minutes. This lets the sauce settle and prevents it from being too runny. Trust me, it’s worth the wait. The aroma fills the kitchen, and it looks so inviting. Serve it warm and watch it disappear! It’s truly a crowd-pleaser and always a hit at my table.