Back in the 60's, before I went into the navy. My oldest cousin from Reading, and WWII veteran who served in Germany following the war introduced our family to HIS version of a PA Dutch Burger.

Like everybody else has described here. He included the bacon, pickles, cheese and ADDED

GOLDEN MUSTARD (like you'd get on a hotdog at a ball game back then).

His trick was...COATING THE BURGER with the Mustard while still on the grill, or in the pan. NO OVEN, that took out the juices.

It was really GOOD.