Boil the eggs. Bring a pot of salted water to a boil over high heat. Gently add the 8 eggs and boil for 6 minutes for soft-boiled eggs. Transfer to a bowl of cold water, let cool for 3 minutes, then peel and set aside.
Prepare the vegetables and meat. Cut the smoked pork belly into small cubes. Thinly slice the leeks.
Make the sauce. Heat a large saucepan over medium heat. Add the pork belly cubes and cook for 2-3 minutes, stirring occasionally, until they start to render. Add the sliced leeks and cook for 2-3 minutes, stirring frequently, until softened. Sprinkle the flour over the mixture and stir for 1 minute. Pour in the meat broth and white wine while stirring constantly. Bring to a boil, then reduce to medium-low heat and simmer for 5 minutes until the leeks are tender. Season with salt, pepper, and a pinch of grated nutmeg. Remove from heat, stir in the crème fraîche, then gently add the peeled eggs, stirring very gently for 1-2 minutes to warm them through.
Serve hot, optionally with boiled potatoes on the side.