- 1 medium eggplant (about 1 1/4 pounds)
- 5 Russet potatoes (about 3 1/2 pounds) peeled and each cut into 6 cubes
- 2 tablespoons olive oil
- 1 pound ground lamb or beef
- 1 tablespoon fresh oregano or marjoram, finely chopped OR 1 teaspoon dried oregano or marjoram
- 1 teaspoon crushed red pepper
- 1 fresh bay leaf
- 1/2 teaspoon ground allspice
- A pinch ground cinnamon
- 1 onion, finely chopped
- 3 to 4 cloves garlic, chopped
- 1/4 cup tomato paste
- 1/2 cup dry white wine
- About 1 cup chicken stock
- 1/2 cup crème fraiche
- About 1/3 cup whole milk
- About 1/8 teaspoon freshly grated or ground nutmeg, to taste
- 1 large egg yolk
- 1 1/2 cups (about 6 ounces) grated Gruyère
- About 1/1 cup (about 2 ounces) grated Parmigiano–Reggiano
Position a rack in the center of the oven; preheat the broiler.
Peel the skin off of two sides of the eggplant and trim off the top. Slice lengthwise into long, thin planks about 1/4- to 1/2-inch thick then dice into small pieces.
Place the cubed potatoes in a medium pot and add enough cold water to cover by an inch. Bring to a boil, salt the water and cook until tender, 10-12 minutes.
Meanwhile, in a large, deep skillet, heat the olive oil, two turns of the pan, over medium- high to high. Add the meat and cook until browned, breaking it up with a spoon, about 5-6 minutes. Add the oregano or marjoram, crushed red pepper, bay leaf, allspice and cinnamon; season with salt and pepper.
Pat the eggplant dry and add to the meat along with the onion and garlic. Cook, stirring occasionally, until the vegetables are softened, 7-8 minutes. Add the tomato paste; stir one minute. Add the wine and stir until evaporated, about a minute. Add the stock, reduce heat to low and simmer until the meat mixture thickens, about 3 minutes.
Drain the potatoes and return them to the hot pot. Add in the crème fraîche and milk; mash until smooth. Add the nutmeg and season. Stir in the egg yolk.
Discard the bay leaf from the meat mixture and transfer to a medium casserole dish. Top with the mashed potatoes and smooth the top with a spatula. Sprinkle with cheeses and broil until browned and bubbling, 3-4 minutes. Serve from the dish into shallow bowls.