Truffled Oyster Gratin with Parsnips and Fennel

steps

1. Melt 4 tablespoons butter in a large saucepan over medium heat. Whisk in the flour to make a roux, stirring frequently for about 5 minutes, until it turns blonde. Add the leeks, garlic, parsnips, and fennel, reduce the heat to low, and cook for another 5 minutes. Slowly add the milk while whisking. Increase heat, bringing to a boil. Add the bay leaf and thyme then reduce heat to low and simmer, stirring occasionally for 15 minutes.
2. Remove the pan from the heat, remove the bay leaf, and season with the salt and pepper. Add the truffle oil and let cool to room temperature, about 35 minutes.
3. Preheat the oven to 400 degrees. Place the oysters in a baking dish in a single layer, then pour the cooled sauce over the top of the oysters.
4. In a mixing bowl stir together the breadcrumbs, 4 tablespoons melted butter, olive oil, Parmigiano-Reggiano, parsley, and tarragon. Sprinkle over the oyster and sauce in the baking dish. Bake for 15−20 minutes, until the sauce bubbles around the edges and breadcrumbs are golden brown.