Preheat oven to 400°F. Line a rimmed baking sheet with aluminum foil.
Arrange the sliced bacon in an even layer on the wire rack that's sitting on a sheet pan or roasting pan. Next, sprinkle the top of the bacon evenly with the brown sugar. (If I were making this to just eat, I'd add paprika and red pepper. But I find the jalapenos offer enough heat when using them.)
Bake for 15-20 minutes, until the bacon, is crisp.
Jalapeno Pimento Cheese
Drain pimento, reserving liquid. In a large bowl, combine cheeses, pimento, jalapeno, mayonnaise, mustard, salt (pinch, optional), and 1 tablespoon pimento liquid.
Mix together until completely combined. Taste and add more salt and mayonnaise if necessary.
For the sandwich
Preheat skillet over medium heat.
Generously butter one side of a slice of bread.
Place bread butter-side-down onto skillet bottom
Spread ¼ cup Jalapeno Pimento Cheese on bread, top cheese with about ⅓ cup bacon chopped.
Butter a second slice of bread on one side and place butter side up on top of sandwich.
Grill until lightly browned then and flip over; continue grilling until cheese is melted and bacon is hot.