A taste of my childhood, my grandmother made the most amazing Egg Custard, as we used to call it! In the absence of lard, or if you are vegetarian, use a white vegetable cooking fat, but NOT margarine, as the white fat gives the pastry its crispness. Serve this tart at room temperature with cream or just "naked"! You can buy these delectable little tarts in most British bakeries, but they always taste better when they have been made at home. This old-fashioned custard tart needs a thick, wobbly filling, so I've used a round tin with sloping sides and a rim, which gives a good depth. The nutmeg is very important to the flavour, so always use it freshly grated and grate it on to a piece of foil, which helps when you have to sprinkle it on quickly when it goes into the oven.