This is absolutely delicious. You can prepare the sauce in advance, just cover and chill until you need it. Serve this with a crisp green salad. If you can't find Lancashire cheese I expect cheddar would work just as well.
Prepare the pastry. Roll out and line a deep 20cm (8 inch) loose-based cake tin. Chill for 30 minutes, then bake blind at 190C for 15 minutes. Remove the paper and cook for another 5 minutes. Leave to cool in the tin.
To make the filling melt the butter in a saucepan on a low heat, blend in the flour, then add the milk a little at a time, stirring continuously.
Beat in the grated cheese, then the egg yolks one at a time. Stir until the cheese has melted. Stir in the chives, parsley and Tabasco sauce. Take off the heat.
Whisk the egg whites in a bowl until they form stiff peaks, then fold them into the mixture. Pour the mixture immediately into the pastry case. Bake at 200C for 30 minutes until it is well risen and golden.