1. Roll out the pastry and use to line a 24 cm (9 1/2 inch) loose bottomed flan ring. Bake blind in the oven at 200°C (400f) mark 6 for 10 -15 minutes until set.
2. Dice 125 g (4 oz) bacon. Lightly fry the diced bacon and the onion together in oil until golden.
3. Mix eggs with yogurt, milk and seasoning; stir in the pan ingredients. Lastly, mix in the spinach, well drained. Pour the mixture into the flan case and bake in the oven at 190°C (375°F) mark 5 for about 30 minutes, until just set.
4. Form the rest of the bacon into little rolls and bake (place in the oven 10 minutes after the flan); use as garnish.