Dried onions: My main divergence from the traditional green bean casserole (aside from it being plant-based) is that I am not using French’s French-Fried Onions because they contain oil and salt. I tried making my own using a few different methods, and didn’t come up with anything I liked. I even dehydrated some onions at home, and just don’t think this is a practical route for most people, as dehydrating takes many hours. But if you want to try dehydrating onions for this dish, feel free. I finally ended up just using some dried minced onion and dried shallots from the spice store, which can be added as a garnish over the whole dish or people can add them if they wish.

Mushrooms: I know a lot of people don’t like mushrooms, so I think they could be substituted with a favorite vegetable like cauliflower, broccoli, peppers, or even cubed winter squash. The sauce would go well with any of these types of substitutions.

Baking dish: You could easily use an 8x8-inch backing dish for this recipe, or any that are around this size. I baked this recipe in the shallow dish shown in the photos here and it worked great. I preferred it since it would look a bit nicer on the holiday table.

Flour: I usually grind my own flour for my recipes, but for this I used some millet flour from the store, because I wanted it to be a very fine texture since it was going into a sauce. I used millet because that's what I had in my cupboard (and is gluten-free), but any type of flour would work I think, including oat or rice.