Cut the pastry sheet into four and prick with a fork. Bake on a baking sheet for 10 minutes at 200c/fan 180c/gas 6, then gently press down the centre of each square.
Cut the gruyère into cubes, and the slices of chorizo into pieces, then scatter over the squares. Crack an egg onto the middle of each and bake for another 5-7 minutes, until the eggs are softly set and the pastry golden. Scatter with parsley.