Pre-heat the oven to 230°C: 450°F: Gas 8
Place cod fillets in the bottom of a round oven dish.
Make a cheese sauce with the butter and flour, milk and grated cheese, pour over fish.
Then make scone dough
Rub the butter into the flour adding the baking powder and pinch of salt.
Add the grated cheese and the egg yolk into the mixture with enough milk to make a workable dough.
Roll out to a thickness of ½ inch and cut into small rounds with a scone cutter.
Place the scone rounds on top of the sauce just covering the surface
Glaze with milk, sprinkle more grated cheese over
Bake for 25-30 minutes or until the scones are golden brown.