Coffee Marinated Steak Sandwich

1: Brew your coffee to your taste. Add it to a bowl, pour in Worcestershire sauce, balsamic vinegar, salt and pepper. Let steak marinate for at least 1 hour or up to 24 hours.

2: Slice onions and mushrooms. Heat a pan to medium heat and begin caramelizing onions. Add mushrooms and stir, letting them release their liquid. Then add balsamic vinegar. Stir until onions are caramelized, then remove.

3: Heat pan to medium-high heat and cook steak to desired doneness. Let rest for 10 minutes, then slice.

4: Slice bread, butter one side and set aside.

5: Mix mayo ingredients together.

6: Place bread in pan over medium heat, butter side down. Spread mayo, cheese, onions, mushrooms, steak, more cheese, then top with another slice of bread, butter side up. Brown one side, then flip and brown the other side.

7: Remove from pan and repeat with other sandwich.

8: Slice, dip into remaining mayo, and enjoy!