A mixture of sweet sausage and red potatoes gets bundled in a flaky puff pastry for an irresistible sandwich alternative.
Preheat oven to 425 degrees. Heat oil in a large saucepan over medium heat until hot but not smoking. Add potatoes, and cook, stirring frequently, until tender, about 12 minutes. Stir in onion and sausage, breaking up sausage as it cooks; continue cooking until meat is no longer pink, about 5 minutes more. Stir in thyme and salt; remove from heat.
Place puff pastry on a lightly floured surface, unfold, and roll out to a 12-inch square. Cut into quarters to get four 6-inch squares. Place one quarter of the sausage mixture in the middle of each puff-pastry square. Gently fold one corner of the square over the filling to the opposite corner, forming a triangle; press edges to seal. Repeat with each remaining square.
Place filled pockets on a rimmed baking sheet, and brush lightly with egg. Bake until golden brown, about 20 minutes. Serve immediately.