3 tbs Vegetable oil
1 medium yellow onion, sliced in half-moons
1 pint button or baby bella mushrooms, cleaned and thinly sliced
1 pound ground beef (my mom would use strips of tender meat, but ground was easier for me)
3 beef bullion cubes
1 cup hot water
1/2 tsp salt
2 tbs ketchup
1 tsp dry mustard
2 tblsp flour
1/2 cup cold water
2 tblsp dry sherry (optional--I used dry vermouth)
1 cup Sour cream
1 package wide egg noodles, tossed in a little butter or margarine