In a medium heated pan, fry the bacon until oil exudes, then add in the onions and leeks.

Let this cool off while making the crust.

When cooled, scoop into the crust.

In a blender, put in the butter, flour and salt, blend for 10 seconds on medium speed (Thermomix 10 seconds on #3). It will look like breadcrumbs.

Add the egg and blend at the same speed for 10 more seconds. (Thermomix: 10 seconds on #3)

The dough would have been formed. It can be used immediately or stored in the fridge for later.

Roll out the dough and spread it to line the pie dish/dishes.

The dough should be a few millimeters above the pan, to cater for shrinkage. Use a knife to cut off any excess.

Poke holes on the bottom of the pie with a fork and freeze. Make the custard and preheat the oven.

Mix the eggs, milk and a pinch of salt and pepper.

Beat the mixture lightly and do not overbeat.

Pour over the filing mixture to 2/3 of the height of the pie dish.

Bake at 200C on the lowest shelf. Pie is ready when the custard puff up a little, which takes 20-25 minutes. Leave it in the oven to cook off if the center is still soft.