As decadent as roasted vegetables can get! Onions, carrots, and potatoes are cooked with clarified butter, bone marrow, and foie gras fat for our Cote de Boeuf Rossini.
Preheat oven to 400 degrees. In a medium stockpot, heat clarified butter over medium-high. Add onions, carrots, and potatoes. Season with salt and pepper; toss to combine. Cook 3 minutes. Stir in marrow and cook, stirring occasionally, 5 minutes. Stir in 2 tablespoons foie gras fat and cook, stirring occasionally, until vegetables are beginning to brown, about 5 minutes more. Add 2 tablespoons water. Transfer to oven and cook until vegetables are tender, about 30 minutes.
Remove from oven. Stir in parsley and remaining 2 tablespoons foie gras fat. Toss to combine.