In a medium bowl, combine the cheese, kimchi and green onions.
1 cup cheddar cheese, ½ cup kimchi, 2 tablespoons fresh green onions
Butter one side of each slice of bread.
4 slices multigrain bread
Spread the other side of 2 bread slices (not the buttered side) with mayo and sriracha. Top each with half of the cheese mixture. Top with the remaining bread slices (the buttered sides should be on the outside).
Heat a large skillet to medium-low heat. Place the sandwiches in the skillet, cover with a lid and cook until golden brown on the bottom, about 3-5 minutes.
Flip them over and cook uncovered for another 3 to 5 minutes, until golden brown and cheese is fully melted.
Slice the sandwiches in half and serve with extra mayo and sriracha on the side, if desired.
Notes
This recipe is best served immediately. If you do happen to have some leftovers though, store in the fridge and reheat them in the pan to retain the crispiness.