Directions

1. To make the pastry, rub the flour, salt, butter and thyme into fine crumbs. Mix in the beaten egg and 1 tbsp ice-cold water, then draw together to a moist pastry, kneading lightly. Wrap with cling film and chill for at least 20 mins.
2. Heat oven to 190C/fan 170C/gas 5. Brush a deep, loose-bottom, 24cm tart tin with oil, then season it. Set a small ball of pastry aside and roll out the rest on a lightly floured surface to a large round, 38-40cm. Lift the pastry into the tin using the rolling pin and press into the sides. Press any cracks together and let the excess overhang.
3. Use a small ball of pastry to press the tart case into the flutes. Save a little more pastry for later (see Step 3 in the Step by step images). Prick the base lightly with a fork and chill the tart case, preferably in the freezer, for at least 30 mins. Cut out a circle of baking paper larger than the tart, scrunch it up, unravel and press into the case.
4. Fill the case with baking beans, stand on a baking sheet and bake for 20 mins. Remove the paper and beans and brush with the remaining yolk. Return to the oven for 5 mins, brush again and return for a final 10-15 mins until glazed and golden. Remove from the oven. Turn the oven to 140C/fan 120C/gas 1.
5. To make the custard, beat together the whole eggs, yolks, creme fraiche, milk and tarragon and season to taste.
6. For the filling, saute the bacon in 1 tbsp oil until browned and beginning to crisp, about 5 mins. Add 2 tbsp oil to the pan and saute the onion and chicory with the bacon, stirring until lightly cooked, about 5 mins. Strain any juices through a sieve, then tip into a big bowl.
7. Heat 2 more tbsp oil and stir-fry the mushrooms over a high heat for 3-5 mins. Strain and mix into the bowl. Wilt the rocket in same pan over a high heat and leave to cool.
8. Mix the cheeses and rocket into the custard and whizz with a hand blender until well mixed, then stir in the rest of the filling ingredients.
9. Put the tart case back into the oven. Leaving the shelf slightly out, ladle as much filling into the case as you can. Try to ladle the solid filling in first, then top up with custard. Push the shelf in and bake for 50 mins-1 hour until the quiche is set in the middle, turning for even baking.
10. Remove and trim the pastry edge so that it's in line with the top of the tin. This is easiest with a small, serrated knife. Cool the tart for at least 1 hour before removing from the tin and serving in slices.