01 -
Preheat the oven to 400°F. Lightly butter a 9-inch deep pie dish or a 2-quart baking dish.
02 -
Cook the sausage in a large skillet over medium-high heat for 7-9 minutes, breaking it into small crumbles, until browned and cooked through.
03 -
Add the butter to the skillet. When melted, sprinkle in the flour and stir for 1 minute, coating the sausage and cooking off the raw flour taste.
04 -
Gradually stir in the milk. Add black pepper, salt, garlic powder, and cayenne if using. Simmer for 4-6 minutes, stirring often, until thick and creamy.
05 -
Spoon the gravy into the prepared dish and let it cool for 5-8 minutes while you prepare the pastry.
06 -
Lay the cold puff pastry over the dish. Trim any large overhang, press the edges lightly, and cut 4 small vents in the top. Beat the egg with water and brush it over the pastry.
07 -
Bake for 22-26 minutes, until the pastry is puffed and deep golden brown. Rest for 8-10 minutes, then sprinkle with chives and serve hot.