I don't have a sonic. I don't think peanut butter with beef and cheese is a good match, better with chicken.
I used to make Chunky Jiff peanut butter and bacon toast-wiches.
Partially toast two slices of a hearty white bread,
then spread on a wisp of butter, then the peanut butter, and layer on the 2 or 3 slices of bacon - close it up with a toast lid and pop it back in the toaster oven till dark golden brown.
Killer!
Sounds like a weird combo, but many Americanised Asian dishes have been successfully combining peanuts with meats, like Chicken Kung Pao and Pad Thai.