Whisk together all of the ingredients, taste and adjust as needed. Set aside.
For the burger:
Click the link above to follow the instructions for the burger. To assemble: place the cheese slices on one side of the brioche bun while toasting to melt. On the lower bun, lay in the burger patty, lettuce, onions (if using) and tomatoes. On the top side of the bun: spread on some of the gochujang sauce, and then the mayo and place on top of the burger. Enjoy!