Heat butter in a medium sauté pan until melted. Add mushrooms at medium-high heat. Add tarragon. Stir to coat and sauté until the majority of the liquid has been cooked out of the mushrooms. Add salt & pepper as needed. Remove from heat and divide mushrooms amongst the two au gratin dishes.

In a medium saucepan over medium heat, melt 1 tablespoon butter. Once butter is melted, add shallots. Saute slightly until they are fragrant and start to become translucent, about 3 minutes. Add white wine. Turn heat to low and simmer.

In a separate, small saucepan, heat egg yolks, stirring constantly until they become thick. Once thickened, add 1 tablespoon butter and orange juice. Stir to combine, then add to white wine-shallot mixture. Add whipping cream and tarragon and stir to combine.

Remove sauce from heat and put in a blender. Blend until combined and whipping cream becomes frothy. Pour back into saucepan and simmer on low heat.

Once rewarmed, drizzle half of the sauce over the mushrooms in the two au gratin dishes.

Preheat oven to 425 degrees Fahrenheit.

Season the two pieces of fish with salt & pepper.

Warm olive oil in a medium sauté pan over high heat. Add seasoned fish and sear lightly (about 2 minutes each side.)

Place one piece of fish over the mushrooms and sauce on each of the au gratin dishes.

Drizzle each piece of fish with the remaining sauce.

Heat butter in a small sauté pan over medium-high heat. Once butter is melted and pan is hot, add slices of banana. Caramelize until lightly golden (about 1-2 minutes each side.) Remove bananas from pan and place slices on top of the sauced fish in the au gratin dishes.

Place au gratin dishes in preheated 425-degree oven. Bake for about 18 minutes or until sauce is bubbly and golden. Remove from oven and let cool slightly before eating.