Start by pre-heating your oven to 200 Celsius. While this is happening, finely grate your Gruyere cheese and, if using thick bacon, slice and dice the bacon then set aside. Heat a large frying pan then render the bacon pieces on a medium heat until they are nicely browned (about 5-10 minutes). When done, remove with a slotted spoon to a pate covered with kitchen towel and leave to cool.

In a large bowl, crack your three eggs and use a hand mixer to whisk thoroughly. In another large bowl, pour in your crème fraiche and use a hand whisk to mix together with the double cream, salt and pepper. Finally, when the bacon is cool enough, add two thirds of the bacon and cheese to the mix and stir together.

When your oven is nearly ready, remove the pastry from your fridge. Take a large tart tin and place on a baking tray then unroll the pastry and place in the tart tin pushing down the middle then the sides. Once done, use a fork to prick the base all over then cover with a sheet of baking paper and add dried chick peas or beans to weigh down (make sure the paper covers the exposed edges of pastry at the top). When the oven is ready, place in the top part and bake for 20 minutes, then remove the baking paper with the chick peas or beans and replace in the oven to bake for another 5 minutes. Once done, place on the hob.

Now take the remaining third of the gruyere cheese and spread over the base of the pastry, then add the remaining third of the bacon. Continue by carefully pouring in the egg/cream/cheese and bacon mix then reduce the heat to 190 degrees Celsius and return to the oven for 25 minutes. When done, remove and leave to cool for 20 minutes.