
This is the EASIEST homemade green bean casserole and it's dairy free! This is the easiest, dairy free green bean casserole and you'll only dirty one pan making it. Make it vegan with vegetable broth, and add chopped mushrooms if that's your thing. Either way, everyone at your table will love it.
Mise en place. Preheat your oven to 400˚F and measure/chop all of your ingredients before you begin.
Blanch the beans. Bring a large pot of salted water to a boil. Blanch the green beans for about 4 minutes, until they’re bright green and just slightly tender. Drain and set aside.
Sauté the aromatics. Heat the olive oil in a large (12-inch) oven-safe skillet over medium-high heat. Add the diced onion and garlic with a good pinch of coarse salt. If you’re adding mushrooms, toss them in now too. Cook for 5–6 minutes, stirring occasionally, until the onions are soft and translucent.
Make the sauce. Sprinkle the flour over the veggies and stir until it soaks up the oil and forms a paste (that’s your roux). Slowly whisk in the broth, then the dairy free milk, making sure everything stays smooth. Season with salt and pepper. Let the sauce come to a simmer and thicken—this should take about 5 minutes.
Assemble the casserole. Stir in the blanched green beans and about 1/2 cup of the crispy fried onions. Mix everything until the beans are coated in the sauce.
Bake it up. Sprinkle the remaining fried onions evenly on top. Bake, uncovered, for 15–20 minutes, or until bubbly and golden brown.
Cool slightly before serving. Let your casserole rest for at least 10 minutes before digging in. The sauce will thicken more as it sits.