Preheat a skillet over medium heat. For each sandwich, generously butter both sides of a slice of multigrain bread. Place bread onto skillet and add a slice of cheese. Top with desired amount of apple and onion jam and 2-3 slices bacon. Butter a second slice of bread on both sides and place on top of sandwich. Grill until lightly browned and flip over; continue grilling until cheese is melted. Repeat with remaining bread and cheese to complete your sandwiches.
CARAMELIZED APPLE & ONION JAM (MAKES ABOUT 1 CUP, ENOUGH FOR 4-6 SANDWICHES)