Mix all slaw ingredients and refrigerate for one hour.
Combine the meats, then make 4 equal size patties, and season each with salt and pepper. Heat a grill or saute pan over high heat, then cook patties 3 to 5 minutes per side, or to your liking. I prefer medium rare. REmove from pan and keep warm.
Place 4 piles of pastrami (or corned beef) in the same pan over medium heat. After two minutes, top each pile with a slice of swiss cheese. Remove when cheese melts.
Over medium heat, melt the butter in a clean pan. Toast the buns in the melted butter, cut sides down, for two minutes.
Assemble Burgers. Place slaw on bottom half of bun. Top the slaw with a burger and the pastrami (or corned beef) cheese pile. Cover with top bun and serve.
notes:
* You can use just 1½ lbs of ground beef instead of all those cuts of beef, if desired. However, I definitely recommend trying it with those cuts at least once!
Recipe by parsley sage sweet at https://parsleysagesweet.com/2010/03/31/possibly-the-best-burger-buns-ever/