met lashing of butter and toast the bagels cut side down. Remove and set aside.
Slice beef across the grains and marinate for 15 minutes.
Pan seared with butter a minute each side. Remove and set aside to rest.
Fry the onions till tender but not too soft so they maintain a CRUNCH.
Add more butter and fry the mushrooms. meanwhile fry your eggs.
Assemble and serve.