For bacon jam: In large skillet fry bacon, in batches if necessary, over medium-high heat, stirring occasionally, until fat is rendered and bacon is lightly browned, about 20 minutes. With slotted spoon, transfer bacon to paper towels to drain.
Reserve 1 tablespoon fat in skillet (reserve remainder for future use or discard). Add onions and garlic; cook until onions are translucent, about 6 minutes. Add pepper flakes and cook another minute. Add coffee, vinegar, maple syrup, brown sugar and bourbon; bring to boil, stirring and scraping up browned bits from skillet with wooden spoon, about 2 minutes. Add bacon to mixture, stirring to combine.
Bring to gentle boil; cook for about 3 minutes. Reduce heat to simmer; cook, uncovered, 60-90 minutes, or until liquid has reduced to syrupy consistency.
Transfer to food processor and pulse until coarsely chopped. Cool and refrigerate in airtight containers up to 4 weeks.
For sandwich: Butter 1 side of each bread slice. Spread opposite side of 1 slice with peanut butter and brie. Spread unbuttered side of other slice with cream cheese and bacon jam. Press bread slices together for sandwich, buttered-sides-up. Grill over medium heat until both sides are nicely browned.
*The recipe makes more jam than you will use for this sandwich. Use remainder for additional sandwiches or applications. Bacon jam can also be purchased in some specialty food stores.
For bacon jam*:
- 1 pound applewood smoked bacon, cut crosswise into 1/2-inch strips
- 1 medium yellow onion, chopped
- 2 garlic cloves, smashed and minced
- Pinch of red pepper flakes
- 1/2 cup brewed coffee
- 1/3 cup apple cider vinegar
- 1/4 cup maple syrup
- 1/4 cup brown sugar, packed
- 1/4 cup bourbon or dark rum