This one is a bit out there and deferent. Tell me how you like it.
3 tablespoons strong brewed coffee
1 tablespoon balsamic vinegar
1 tablespoon extra-virgin olive oil
1 tablespoon brown sugar
2 cloves garlic, minced
1 teaspoon whole black peppercorns, crushed
1/2 teaspoon salt
Whisk coffee, vinegar, oil, sugar, garlic, peppercorns and salt in a glass dish large enough for meat to lie flat. Add steak and turn to coat. Cover and refrigerate for at least 1 hour or up to 8 hours
That 1 tablespoon of brown sugar is not going to amount to much bro. Most of it will get cooked off during cooking any way.