For the Potatoes
- 3 large russet potatoes, pricked all over with a fork
- 1 pound celery root, peeled and cut into cubes
- 4 tablespoons butter
- 2 egg yolks plus 1 egg
- Celery salt
- Freshly grated nutmeg
- Splash of heavy cream
For the Meatloaf
- 6 tablespoons butter, divided
- 1 cup panko or homemade coarse breadcrumbs
- 1 teaspoon celery salt
- 1/4 cup parsley, finely chopped
- 1/2 cup cloudy apple cider
- 1/2 pound mushrooms, finely chopped
- 1 teaspoon fennel seed, 1/3 palmful
- 4 shallots or 1 small onion, finely chopped
- 2 to 3 small ribs celery and leafy tops, finely chopped
- 1 Honeycrisp, Jona Gold or Braeburn apple, peeled and finely chopped
- 2 tablespoons thyme, finely chopped
- 2 tablespoons sage, thinly sliced
- 1/4 cup Calvados, brandy or dry sherry
- 2 pounds ground beef, pork and veal mix
- 1 cup roasted or jarred chestnuts, optional, finely chopped
- 1/4 pound, 1 cup, shredded sharp white cheddar cheese
- 1/4 cup grated Parmigiano-Reggiano cheese
- 2 egg yolks
For the Gravy
- 4 tablespoons butter
- 1 teaspoon coarse black pepper
- 3 tablespoons flour
- 3 cups veal or beef stock
- 1 tablespoon Worcestershire sauce
For Duchesse potatoes, preheat oven to 400°F. Roast potatoes on a baking sheet for 1 hour and 15-20 minutes; let cool. Remove potatoes from skins and pass them through a ricer.
Bring a medium saucepot of water to a boil, salt water and cook celery root until very tender, 20 minutes. Drain and pass through a ricer; add to potatoes. Combine with butter and egg yolks, season with celery salt, pepper and nutmeg. Fit pastry bag with 3/4-inch star tip. Line a baking sheet with parchment paper, pipe out 12 cones 2 1/2-inches wide and a couple inches high. Beat egg with cream and lightly brush the cones.
For the meatloaf, melt 2 tablespoons butter over medium heat in a small skillet. Add breadcrumbs, season with celery salt and pepper, and toast to golden. Remove from heat and cool. Toss toasted breadcrumbs with parsley and moisten them with apple cider. Set aside.
Melt 4 tablespoons butter over medium heat. Add mushrooms and fennel seed, and cook to brown lightly then season with salt and pepper. Add shallots, celery, apple, thyme and sage, and cook to soften 6-8 minutes more. Deglaze the pan with Calvados, brandy or sherry and remove from heat to cool.
Season meat with salt and pepper, and add the cooled mushroom mix, cooled breadcrumbs, cheeses and egg yolks, and mix to combine. Form a loaf on a parchment-lined baking sheet and bake on a center rack at 375°F for 1 hour. Add Duchesse potatoes after 15 minutes and bake 45 minutes to crisp.
For the gravy, melt butter over medium heat in saucepot, add pepper and whisk in flour. Bring to a bubble, add stock and simmer to thicken. Add Worcestershire to taste.