Preheat the oven to 190°C/170°C fan-forced and place a baking tray inside. Line four 7.5cm (base) pie tins with shortcrust pastry, trim the excess, and prick the base with a fork. Freeze for 15 minutes until firm.
Heat oil in a frying pan over medium-high heat until shimmering. Add bacon and cook, stirring occasionally, for 5 minutes until golden and crisp. Transfer to a plate lined with paper towel to drain excess oil.
In a bowl, mix together bacon and chives. Then crack 4 eggs into the same bowl and whisk until smooth. Divide the whisked eggs between pastry cases. Top with the bacon mixture and parmesan. Finish by cracking 1 egg into each pastry case and season with pepper.
Place the tins on a preheated baking tray in the oven. Bake for about 20 minutes until the eggs are just set and the pastry is golden. Let the pies stand in the tins for 5 minutes before serving.