Cornish pasty is a traditional British pastry that can be prepared with the help of a food processor. Start by blending flour, butter, and salt in the food processor to make the pastry dough. Roll out the dough and cut it into circles. In a separate bowl, mix together diced beef, potatoes, onions, and seasonings. Place the filling on one half of each pastry circle, fold over, and crimp the edges. Bake until golden and enjoy this savory handheld meal.