Make sauce. In a bowl, mix together soy sauce, honey, hoisin sauce and srirracha sauce.
Make a deep cut into each bun horizontally (don’t cut completely) .Spread butter (1 tablespoon for each bun) on the cut side and place on a baking sheet, butter side up. Bake in 350 degrees F oven for 3-4 minutes until lightly toasted. Take the baking sheet out and keep the bus warm covered with aluminum foil.
In a fry pan, heat sesame oil and cook garlic over medium-low heat until fragrant. Add onions and cook until tender. Add beef and cook until beef are cooked through. Add the sauce and toss to coat. Add salt and black pepper to taste.
Turn off the heat and place cheese on the beef mixture, cover and let stand until cheese melt.
With spatula or slotted spoon, take the beef mixture evenly and put on each bun. Close the sandwiches.