Pre-heat the oven to 180⁰C.
Grease a lasagne tin 20cm x 24cm.
Unroll the pastry sheet and give it a little roll with a rolling pin to slightly stretch the width to fit the tin.
Lay the sheet over the tin and press into the corners gently.
Trim off excess pastry. (Use for cheese straws etc)
Sprinkle ¾ of the cheese over the base and then scatter over the pulled gammon.
Sprinkle on the rest of the cheese.
Put the eggs, milk, onion, nutmeg, salt and pepper in a bowl and whisk together.
Pour the mixture over the cheese and ham.
Fold the pastry sides down over the egg to encase it.
Bake on the bottom shelf for 38 – 40 minutes until golden and pastry is thoroughly cooked.