How to Make It
In a medium bowl, whisk the flour with the baking powder, salt, pepper and nutmeg. Add 6 tablespoons of water and mix with a wooden spoon until a shaggy dough forms. Turn the dough out onto a lightly floured work surface and knead until smooth, about 5 minutes. Transfer the dough to a small bowl, cover with plastic wrap and let rest at room temperature for 1 hour.
Line a baking sheet with parchment paper. Roll the dough into a 1/2-inch-thick rope, then cut into 1/2-inch pieces. Transfer the dumplings to the prepared sheet and cover with a damp kitchen towel.
In a large enameled cast-iron casserole, melt the butter. Add the onion, carrots and celery and season with salt and pepper. Cook over moderate heat, stirring occasionally, until softened, about 10 minutes. Add the garlic and nutmeg and cook, stirring, until fragrant, about 1 minute. Stir in the stock, bay leaves and potatoes and bring to a boil. Add the dumplings, cover and cook over moderately low heat, stirring occasionally, until the dumplings are puffed and cooked through, about 30 minutes. Stir in the cream and season with salt and pepper. Discard the bay leaves and serve.