I will say right off that you can make this easy, short-crust pasty dough recipe in the same amount of time it takes to use far inferior, pre-bought dough. That said, if you have some pizza dough and feel that you must use it up, go for it. I know it’s not technically Cornish, nor is it as flaky as the one below, but it would work.

Steps

1. Make the dough: Cut the butter into the flour until crumbly. Add the water. Form the dough into a ball. Keep the ball in a cool but not cold place — the windowsill in your kitchen, for example.
2. Make the filling: Sauté the meat and onion in a pan with the dot of butter and some salt and pepper. Turn off the heat when the meat is cooked through and the onion is transparent.
3. Preheat the oven to 350 degrees.
4. Assemble the pasties: Roll the dough onto a floured surface until about ¼-inch thick. Using a saucer or small plate as your guide, cut circles from the dough. (I made five, though this recipe is probably best used for four portions.) Arrange a thinnish layer of mashed potato in the center of each circle. Top with thawed frozen peas and/or corn. Add a layer of meat and onions. Top with another layer of potatoes to act as glue so everything doesn’t spill out. Brush the edges of the circle with the beaten egg. Bring the edges up to the center of the circle and crimp or press together firmly, folding over as you go.
5. Bake for about 35 minutes or until the pasties are golden brown.