1. Preheat the oven to 200(C/400(F/Gas Mark 6. Place the flour in the bowl of a food processor and add the chilled, diced butter. Pulse until the mixture resembles fine breadcrumbs. Tip out into a bowl and stir in the Cheddar cheese.
2. Mix together the egg yolk with the chilled water, and sprinkle over the mixture. Stir through well with a knife, then bring the pastry together with your hands.
3. On a floured surface, roll out the pastry and use to line an 8 inch fluted, loose bottomed tart tin. Chill for at least 30 minutes.
4. Line with greaseproof paper, fill with baking beans and bake the pastry case for about 15 minutes, until pale gold with no greasy patches. Remove the greaseproof paper and baking beans and leave to cool.
1. Meanwhile place the shallots, cut side down, in a roasting tin. Drizzle over the oil and dot with butter. Roast in the preheated oven for 15 minutes, until softened and golden, then turn the oven down to 170(C/325(F/Gas Mark 4.
2. Fry the diced bacon until crisp and place in the bottom of the tart case. Arrange the shallots, cut side down, on top.
3. Beat the eggs and egg yolks and add the cream and crème fraiche. Season and stir in the cheese and chives.
4. Pour the custard mixture over the top of the shallots, and cook the tart for 40 minutes until set.
5. Serve warm, cut into wedges, with a rocket salad.