In a large pot steam or par boil the sliced green beans for 3-4 minutes. Place in an ice water bath to stop the cooking process, drain, and set aside.

In a frying pan, cook the bacon until lightly crispy. Remove and place on a paper towel to remove the grease and set aside for later. Heat the remaining oil to medium-high heat and add in the sliced onions or shallots that will be used for the topping. Cook until crispy and remove and set aside.

In the same pan, cook the sliced mushrooms, remaining diced onion, and garlic in the bacon fat (about 5-6 minutes). Add the fresh thyme, rosemary, and season with salt and pepper. Stir in the coconut aminos/ soy sauce and Worcestershire sauce.

Next, sprinkle in the xanthan gum and mix it in with mushroom mixture and stir until dissolved. Finally, pour in the stock and heavy cream. Mix with a spatula or whisk until the mixture begins to thicken. It should coat the back of a spoon when it has reached the right thickness. Be patient and avoid adding more xanthan gum (this will make the mixture slimy and not appetizing). Next, stir in the cheese slowly until it is mixed in (this will add some thickness to the sauce as well).

Combine the mushroom gravy with the green beans.

Pour the mixture into a 9x13 baking pan or leave in a 12" cast iron skillet (pictured). Cover with foil and bake at 350 F for 30 minutes. Remove the foil and let the top brown slightly the last 15 minutes or so.

Remove from the oven let rest for 10 minutes so the sauce can set a bit (prevents it from being too runny) and serve. If you make this ahead of time, store the bacon separate from the green bean and mushroom gravy. If the green bean casserole is cold from the fridge, you may have to add more baking time or remove it from the fridge 1-2 hours ahead of time to allow it to warm up.