Serious Eats: Recipes
The Ultimate Homemade Green Bean Casserole
Note: You can use canned fried onions or shallots instead of making your own in step one and two. For better results, look for fried shallots in a Thai or Vietnamese market—but French's will do just fine if that's what you prefer. Slice the shallots on a plastic mandoline (like a Benriner) to get even results. The oil used to fry the shallots can be saved in an airtight container away from the light for up to 3 months. Use it for stir-fries or in salad dressings.
To Make Ahead: Fried shallots can be made up to a month in advance. Mushroom sauce can be made up to 4 days in advance. Assembled casserole can be made and stored up to two days in refrigerator. To complete, cover with foil and heat in preheated 350°F oven until hot, about 30 minutes. Uncover and cook until bubbly, about 10 minutes longer. Top with 1 cup shallots and serve.