Preheat the oven to 350 degrees and lightly grease 12-cup muffin pan.
Roll the dough out to ¼ inch thickness on a lightly floured counter and cut out 12 circles approximately 5 inches in diameter. Use the circles to line the cups of the muffin pan, gently pleating the sides of the dough as you ease it into the molds. Place ½ teaspoon of the mustard into the base of each pastry “basket” and top with a little of the bacon.
Break an egg into a cup and spoon the yolk into the pastry basket. Then add enough of the white to fill the pastry basket about two thirds full. Do not overfill. Season to taste with pepper and sprinkle with grated cheese evenly over the tops of the pastries. Bake for 20-25 minutes, or until the egg is set and the cheese is golden brown. Serve warm, sprinkled with chopped parsley.