Halve and deseed the jalapeno peppers, then stuff them with the cream cheese filling. Bake the stuffed jalapeno peppers for 20 minutes at 400F.
Place slices of bread on a plate or kitchen board, covered by parchment paper and butter on side of each bread slice.
Turn the slices over so that the non-buttered side is facing up and add slices of Jack cheese to one sandwich slice and cheddar cheese to the other.
Place 2 slices of bacon on one slice of each sandwich and 2 stuffed jalapeno popper halves on the other slice.
Combine the slices together and transfer the assembled sandwiches to a hot skillet. Cook the sandwiches until the cheese is melted and the bread is golden.