Prepare the crust by rubbing the butter into the flour by hand or using a mixer. Add the salt. Then, add the water one tablespoon at a time until the dough comes together (it shouldn't be sticky or so dry that it doesn't hold together properly).
On a lightly floured surface, roll out the pastry until it is large enough to fit your dish (mine was 26cm across). Place it in the dish, smoothing down and pressing up to the sides. Gently trim and major excess from the sides but note that when baking, the crust will shrink so don't remove too much. Pop in the fridge for 30 minutes and pre-heat the oven to 220°C.
Prick the base of the crust all over with a fork and then cover with baking paper topped with dried peas (or whatever else you use to bake blind). Bake for 10 minutes, remove the baking paper and peas and bake for a further 10 minutes. Remove from the oven while you prepare your filling and reduce the oven temperature to 180°C.
For the filling: fry the bacon until crispy. Set to one side. Fry the onion and add to the bacon. Sprinkle over the base of the crust along with most of the cheese. In a bowl, beat the eggs, cream and milk together then add the seasoning to your taste. Pour over the other ingredients.
Bake for around 25 minutes then sprinkle the remaining cheese over the top and bake for a further 10 minutes or so. The quiche is ready when it no longer wobbles when you give it a little shake. Serve warm or cold with salad or chips. Enjoy!