Cook the bacon in a large pan over medium high heat until crisped and fat is rendered. Add the Lucky Food Spicy Kimchi Hot Sauce, kimchi, and brown sugar to the pan. Pan fry for a few minutes, leaving it undisturbed for a few minutes at a time so it dries out and gets a little bit caramelized. Season with black pepper. Transfer to a bowl and wipe the pan clean.
Layer your sandwiches: a slice of sourdough, two slices gruyere cheese, kimchi mixture, two slices American cheese, and a second slice of sourdough. Spread butter or mayo over the top and bottom of the sandwich.
Heat the same skillet to medium heat; add the sandwich and cook for a few minutes on each side until golden brown. Cut and serve. Enjoy!