cook noodles in salted water

while noodles are cooking melt butter in a medium sauce pan

once butter is melted slowly add flour and dry mustard. constantly stir for about 5minutes on low heat. make sure there are no lumps.

add milk, onion, worchester sauce, salt and pepper to taste. cook over medium low heat until sauce begins to thickening. (about 10minutes)

temper in lightly beaten egg

stir in 3/4 cheese a little at a time until completely melted

pour over buttered noodles and mix until all noodles are coated

bake 20mins at 350° covered.

mix remaining cheese in with noodles and sauce.

remove cover and bake about 10more minutes until top is golden brown