1 cup (250 ml) homemade or store-bought demi-glace
1 tablespoon (15 ml) Cognac or brandy
2 tablespoons (30 ml) chopped parsley
Salt and pepper
Remove the bone marrow. To do this, press the marrow with your thumb so as to push it out of the bones. If the marrow is stuck, warm the bones in a 180 °C (350 °F) preheated oven for 8 to 10 minutes and press again. If necessary, remove with a small knife. Cut the marrow into 1-cm (1/2-inch) thick slices. Set aside.
In a small saucepan, soften the shallots in the butter. Add the sugar and cook for 1 minute. Deglaze with the wine and add the thyme. Bring to a boil and reduce by half, about 10 minutes. Add the demi-glace. Bring to a boil and simmer for about 10 minutes or until the sauce is syrupy. Add the cognac. Remove the thyme. Season with salt and pepper. Set aside.
In a skillet over high heat, quickly brown the marrow on each side. Deglaze the skillet with the sauce and heat gently until the marrow is cooked. Add the parsley. Adjust the seasoning.