Preheat oven to 200°C. Lightly grease a fluted 3cm deep, 23cm base, loose-base flan pan.
Line base and sides of flan with pastry. Trim excess. Line pastry with baking paper. Half-fill with dried beans or rice. Bake for 10 minutes. Remove paper and beans. Bake a further 10 minutes or until golden.
Heat oil in frying pan over medium-high heat. Add onion and bacon. Cook for 3 minutes. Drain on paper towels. Cool. Sprinkle over pastry. Top with cheese.
Reduce oven temperature to 180°C. Whisky remaining ingredients and salt and pepper in a jug. Pour over bacon. Bake for 30-35 minutes or until set. Stand for 5 minutes. Serve.