Day Before: Marinate the oxtail pieces for 24 hours in your prepared marinade, incorporating the old plum for depth of flavor.
Day Of: Drain the oxtail. In a cast-iron casserole, sear the pieces in peanut oil for 4 minutes per side until golden. Decant the juices and degrease the pan. Add the drained marinade garnish (including mushrooms and garlic), sauté briefly, then sprinkle with flour. Cook for 5 minutes, stirring with a wooden spatula. Deglaze with the marinade wine, add a bouquet garni, and simmer uncovered over low heat for 45 minutes.
Add the oxtail pieces, cover with water, bring to a boil, and stir in the beef bouillon cubes. Cover and braise in a low oven (180°C) for 3½–4 hours, until the meat pulls easily from the bone. Remove oxtail to cool, then debone. Strain the sauce through cheesecloth and reduce over low heat, skimming impurities.
Peel the tomatoes, slice off the tops with stems, and hollow them out carefully without piercing the skins. Sprinkle coarse salt inside and drain upside down.
For the sauce: Sweat 2 chopped shallots in butter. Add Malaga wine and reduce. Incorporate some oxtail braising liquid, reduce by one-third, then blend with foie gras trimmings. Strain through cheesecloth.
In a sauté pan, cook the remaining 3 chopped shallots, add the deboned oxtail, and brown. Add 3 ladles of sauce and reduce. Stir in the sautéed mushrooms. Keep warm.
Assembly and Finishing: Briefly heat each tomato in boiling water. Fill with the oxtail mixture, allowing it to cascade over one side. Top with a seared foie gras escalope—the dripping fat enhances the stuffing. Spoon sauce over the plate and serve immediately.
Source: Fabienne Labeyrie’s Foie Gras
