Prepare burger patties by carefully forming ground beef. (Before grilling, we'll season lightly, but not yet!)
Heat 2 medium pans over medium heat.
In one pan, melt the butter.
In the other pan, add the bacon and cook it until it's nice and crispy.
While the bacon is cooking- to the pan with the butter, add the onions, salt, and pepper. Reduce the heat to low.
Cook the onions for about 10 minutes, stirring often. Watch the heat - you don't want them to burn.
Reduce heat to low, and in the raspberry preserves, and cook for another 10 minutes, stirring often.
Preheat your grill on high heat.
Liberally salt and pepper both sides of the burger patties, and then throw the burgers on the grill.
When they're halfway done cooking (about 5 minutes), flip them.
Cook them for a few more minutes, and then add the cheese and bacon on top.
Once the cheese is nice and melty, place the burger on the bottom of the bun and add the raspberry caramelized onions on top.