01 -
Cook the sausage in a large skillet over medium heat until browned, breaking it into smaller pieces as it cooks. Sprinkle flour over the cooked sausage, stir thoroughly, and cook for 2 minutes.
02 -
Gradually pour in milk while stirring constantly. Increase heat to medium-high until mixture comes to a boil. Reduce heat and simmer until gravy thickens, about 5 minutes. Season with salt, pepper, sage, and red pepper flakes if using.
03 -
Preheat oven to 375°F (190°C). Roll out one sheet of puff pastry and line the bottom of a 9-inch pie dish, allowing some overhang around the edges.
04 -
Pour the sausage gravy into the pastry-lined dish, spreading evenly. Roll out the second sheet of puff pastry and place over the top. Trim excess pastry and crimp edges to seal. Cut several small slits in the top crust for steam to escape.
05 -
Place pie on the middle rack of preheated oven and bake for 25-30 minutes, until pastry is golden brown and flaky. Let cool for a few minutes before slicing and serving warm.