In a large mixing bowl dissolve yeast and 1 teaspoon sugar in 60ml water; let stand for 10 minutes.
Add salt and remaining water to yeast mixture. Stir in 400g of the flour then beat until smooth. Add enough remaining flour to form a soft dough.
Turn onto a floured surface then knead until smooth and elastic; about 6 to 8 minutes. Place dough in an oiled bowl turning once to grease top. Cover and let rise in a warm place until doubled; about 1 hour.
Combine the cornflour and milk then mix until smooth.
Punch dough down. Shape into two loaves. Place in two oiled 1kg loaf tins. Cover with the 'tiger paste' by brushing it on liberally with a pastry brush. Cover and let rise until doubled; about 1 hour.
Bake at 180 degrees C for 35 to 40 minutes.
You'll see the 'cracking' appear on the crust as it bakes. Once bread is done remove from tins and cool on wire racks.