Heat the milk with the bayleaf, bringing it almost to the boil. Turn off the heat and leave to infuse for 20 minutes or so. Remove the bayleaf, strain and return the milk to the pan then bring back to the boil.
Sprinkle in the semolina slowly, stirring until thick. Cook gently for 3-4 minutes then remove from heat.
Stir in half the grated cheese and the mustard powder then season with salt, pepper and nutmeg.
Turn onto a large, flat wetted baking tray and spread evenly to a depth of about 1 cm. Leave until quite cold then cut into rounds using a wetted 3 cm cutter.
Place rounds in overlapping rows. Sprinkle with the remaining grated cheese and dot with the butter.
Place under a moderately hot grill for 15-20 minutes until crisp and golden.
SErve with a tomato sauce and a green salad or vegetable.