To make the sauce, gently simmer the shallots in the white wine or vermouth until reduced slightly. Add the cream and bring to a boil. Whisk in the butter, piece by piece while the sauce is boiling. Reduce heat to medium and add yellow miso and whisk to incorporate. Season with salt and white pepper to taste. Set aside in a warm place.
To cook the mushrooms, heat the clarified butter on high. Add the mushrooms and cook until crispy. Add in the peeled grapes and garlic cloves, bringing the heat to medium. Add the unsalted butter and stir. Season with salt and pepper to taste and garnish with parsley and breadcrumbs.
To cook the turbot, melt the clarified butter on low heat. Season the turbot with salt and pepper on each side. Add the fish to the pan on low heat and cook until done. Plate with beurre blanc sauce and cooked mushrooms. Garnish with sorrel.