Bring a gallon of water and 2 tablespoons of salt to a boil in an 8-quart saucepan.
Add the green beans and blanch for 5 minutes.
Drain in a colander and immediately plunge the beans into a large bowl of ice water to stop the cooking.
Drain and set aside. See notes for recipe steps if you would rather roast the green beans.
Melt the butter in a 12-inch cast iron skillet set over medium-high heat.
Add the mushrooms, 1 teaspoon salt and pepper and cook, stirring occasionally, until the mushrooms begin to give up some of their liquid, approximately 4 to 5 minutes.
Add the onion, garlic, and coconut aminos and continue to cook for another 1 to 2 minutes.
Add the cashew cream and mix well.
Add the broth and simmer for 1 minute.
Decrease the heat to medium-low and add salt, pepper, onion powder, and garlic powder.
Cook over low heat until the mixture thickens, stirring occasionally, approximately 6 to 8 minutes.
Season green beans with salt and pepper. Add green beans to skillet with the sauce and mix until the green beans are well covered. Taste and adjust seasoning as needed.
Pour the green beans and sauce into the 9 x 9 baking dish. Bake for 30 minutes.
While baking,
make the bacon if using.
Remove from the oven and top with crispy onions and optional bacon, if adding.
Bake for an addition 15-20 minutes, or until green beans are tender and bubbly.
Serve warm!