In large fry pan cook the brat & hash brown patties until done. Meanwhile slice the hard rolls & put on serving plates. Once brat & hash browns are done remove & keep warm on covered plate. Fry eggs (over easy makes the best for these) and break the yolk to make more even. While eggs are cooking put Mustard on rolls (I love a good stone ground brown mustard on these) and ketchup if desired. Assemble brats, onion and hash brown pattie onto roll. Add slice of cheese on top and cover with fried egg. I've added a touch of saurkraut too and love it but some people don't really care for that at breakfast so I usually serve it on the side.