The Food Lab: The Ultimate Homemade Green Bean Casserole

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[Photographs: Vicky Wasik. Video: Natalie Holt]

The classic Campbell's green bean casserole is a staple on many Thanksgiving tables. But there are easy ways to upgrade the out-of-the-can version, without transforming it into something unrecognizable.

First things first: If you're intimidated by the length and number of steps in the recipe attached here, bear in mind that you don't need to use the whole thing. You can use canned fried onions instead of frying your own. Or, to make it even easier, stick with two cans of cream of mushroom soup instead of making your own creamy mushroom sauce.

Because, if the only thing you do is substitute real blanched green beans for the canned variety, you're already giving your green bean casserole a major upgrade. Make your own mushroom sauce out of real mushrooms instead of canned cream of mushroom soup, and you can proudly say good-bye to Sandra Lee. Go the whole nine yards and make the fried shallots yourself, though, and you can proclaim that a "semi-homemade" green bean casserole is a thing of the past.

How to Make Green Bean Casserole From Scratch

Step 1: Fry Your Own Shallots

Crispy fried shallots in a metal strainer

My fried shallots are inspired by Thai-style fried shallots, something that you should have on hand in your kitchen all the time. I make mine in batches of a couple pounds. (To cook more than what's called for in this recipe, just increase the amount of oil to keep them covered.)

A mandoline makes quick work of the shallots, and yields perfectly thin and even slices. Simply add them to a pan or wok, cover with oil, turn your heat up to high, and stir. The shallots will soften and then turn a light golden brown, at which point you can strain them into a bowl. Be sure to reserve the oil, though—we'll be using it again in a minute.

Blot the strained shallots with paper towels until the towels appear dry. Once cooled, the shallots will keep in an airtight container for up to a month. Add them to sandwiches and soups, use them as a garnish for cooked meats, or just eat 'em out of hand, straight out of the jar.

Step 2: Swap the Cream of Mushroom Soup for a Homemade Sauce

The back of a spoon coated in a homemade creamy mushroom sauce

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For my homemade mushroom sauce, I start by smashing the mushrooms with a skillet. Not only is it an extremely satisfying procedure, but it creates imperfect chunks of mushrooms, just like you find in the canned stuff.

I sauté the mushrooms in that aromatic shallot oil, along with a cube of butter for some extra rich and nutty flavor. Once they've begun to sizzle, after about five to 10 minutes, I stir in some minced garlic, then add flour to thicken the base, stirring until it forms a light golden-blond roux.

Whisking in a mixture of heavy cream, chicken stock, lemon juice, and soy sauce adds richness, moisture, acidity, and a burst of umami that coaxes out the mushrooms' natural savory character. I bring the sauce to a boil, then simmer until its consistency is slightly thinner than pancake batter.

Step 3: Use Fresh Green Beans

Blanched green beans in a metal bowl

Using fresh green beans is hands down the simplest way to upgrade your casserole. For the brightest flavor and a crisp-tender texture, I blanch the trimmed beans in salted boiling water for five minutes, then shock them in an ice bath to halt the cooking process.

Step 4: Putting It All Together

Assembling the casserole couldn't be simpler: Just combine the green beans, mushrooms, and a cup of the shallots in a bowl, and stir to evenly distribute all the ingredients. Transfer the mixture to a baking dish, bake at 350°F (180°C) for 15 to 20 minutes until it's hot and bubbly, and top with more shallots to serve.

How to Make Green Bean Casserole Ahead of Time

Finished green bean casserole topped with crispy fried shallots

If you want to help streamline your Thanksgiving Day prep, making your green bean casserole in advance is a no-brainer. Start with the fried shallots, which can be made up to one month in advance and kept in an airtight container. The mushroom sauce (steps six through 10 in the attached recipe) can also be made up to four days in advance.

Two days before serving, you can assemble the entire thing—beans, mushroom sauce, and one cup of the fried shallots—in a baking dish and refrigerate. To complete the casserole, cover the dish with foil and stick it in a preheated 350°F (180°C) oven until hot, about 30 minutes. Uncover and continue cooking until it's bubbly, about 10 minutes longer. Top with an additional cup of fried shallots, then serve.