Cook the spaghetti in a large saucepan of salted boiling water until 'al dente'—about 11 minutes.
Meanwhile heat the butter and oil together in a saucepan and saute the onion in it until soft...
Melt the dripping in a saucepan and stir in the flour.
Cook over low heat for about 15-20 minutes until the roux is cooked to a deep golden brown.
Gradually add the stock, stirring vigorously all the...