Pour canola oil to a large heavy bottom pot to cover the bottom by two inches. Heat over medium heat to 350°F.

While the oil is heating, add 1/2 cup of the gluten free flour, black pepper, garlic salt, and cayenne pepper to a medium sized bowl and whisk together. Add the sliced shallot rings and toss to coat in the flour mixture.

When the oil is hot, shake of the excess flour from the shallots and fry the shallots in batches until golden brown, 2-4 minutes.

Use a slotted spoon or spider to remove the shallots from the oil and drain on a paper towel lined plate. Immediately season with salt and repeat the frying process until all the shallots are fried.

The shallots can be made and refrigerated a few days ahead of making the green bean casserole. You can also freeze them and add them to the casserole frozen.

Trim the tops of the green beans and then cup the green beans in half. Fill a large pot half-way with water and bring to a boil.

While the water is heating up, fill a large bowl with ice and cold water.

When the water comes to a boil, add 1 tablespoon sea salt to the water. Then add half the green beans. Boil the green beans for 2 minutes then remove with a slotted spoon and place the green beans in the ice cold water (which stops the cooking). Remove the green beans from the ice water, place in a colander, and set aside.

Repeat the blanching process with the remaining green beans until all of the green beans are cooked.

The green beans can be blanched up to two days before making the rest of the green bean casserole – just blanch and refrigerate until ready to use.

Preheat oven to 375°F and grease a 13x9” casserole dish with 2 tablespoons butter.

Heat the remaining 2 tablespoons butter and the olive oil over medium heat in a large skillet (a 12-14 inch skillet is best).

When the butter is melted and the oil is hot, add the mushrooms and cook until slightly softened, about 8-10 minutes. Add the chopped shallots and garlic and cook until the shallots are softened, about 5 minutes. Season with salt and pepper.

Add the sherry to the mushrooms and stir well, scraping up any bits that are stuck to the pan. When the sherry is nearly evaporated, stir in the remaining 1/4 cup gluten free flour. Stir well to coat all the mushrooms and cook for 1 minutes.

Slowly stir in the chicken broth and the half & half. Continue to heat and stir occasionally until the mixture comes to a simmer. Add in the green beans and stir well, coating all the green beans. Season with salt and pepper to taste.

Transfer the green bean mixture to the prepared baking dish and bake for 20 minutes.

After 20 minutes, top the green bean casserole with the fried shallots and bake for an additional 5-10 minutes or until bubbling and the top is browned.

Let the casserole sit 5-10 minutes before serving.