Heat a skillet over medium-low to medium heat.
Lay out four pieces of bread, and top with the sliced cheese, then the serrano chiles.
Divide the boysenberry preserves between the remaining slices of bread, and place the preserve side of the bread down on top of the serranos to complete the sandwich.
Use one tablespoon of butter both sides of one sandwich, repeat for the others, and place in the skillet for 4-5 minutes per side, or until the cheese is melty, and the bread is golden brown!
I used roughly one serrano, sliced thinly for one sandwich, and it was spicy. If you are not a lover of spice, use half a pepper. If you like only a teeny bit, use one slice for each quadrant of the sandwich (four slices, one per corner). If you despise spice, leave them off altogether.