Preheat the oven to 200° C.
Bring the broth to a boil in a large saucepan. Add the Tortellini and switch off the flame immediately. Season with salt and pepper to taste. Ladle the Tortellini and broth into ovenproof bowls. Top with grated Parmigiano Reggiano cheese and chopped chives and drizzle with oil.
Brush the edge of each bowl with egg wash (mixing egg yolk with milk) and top them with a disk of puff pastry pressing the edges to stick the pastry to the bowls. Use exceeding pastry to decorate the top. Brush the pastry with egg wash and bake 15-20 minutes until the crust is golden brown.
When you break the crust keep away from the heat and let it rest for a couple of minutes before serving.