Place the flour and salt in a bowl, then
rub in the lard until the mixture resembles breadcrumbs. Stir in the
remaining dry ingredients. Gradually add enough milk and water to make
a stiff dough. It will not take very much. Roll out on to a greased
baking (cookie) sheet to about 1 cm/0.5 in thick. Glaze with beaten
egg. Draw a criss-cross pattern on the top with the tip of a knife.
Bake in a preheated oven at 160°C/325°F/gas mark 3 for about 20
minutes until golden. Allow to cool, then cut into squares.