Peel the potatoes, rinse them, and cut into pieces. Steam until tender.

Mash the potatoes and mix in 1 egg, then add a mixture of heavy cream, milk, salt, pepper, and grated nutmeg. Keep warm.

Sauté the onions in a drizzle of olive oil, add the ground beef, and cook until browned. Season with salt, pepper, and granulated garlic. Add the water and bouillon cube. Simmer gently for 10 minutes.

Remove from heat, stir in 2 egg yolks, and adjust seasoning if needed.

Preheat the oven to 425°F (210°C).

In a buttered baking dish, spread a layer of mashed potatoes, then the meat mixture, and cover evenly with the remaining mashed potatoes. Top with shredded cheese.

Bake for about 10 to 15 minutes, until golden brown.

Serve immediately on its own or with a green salad.