Steps
1. Marinate beef strips in brewed coffee, soy sauce, brown sugar, minced garlic, salt, and pepper for 15 minutes.
2. Heat olive oil in a pan over medium-high heat.
3. Add onions and bell peppers, stir-fry for 3-4 minutes until slightly tender.
4. Add marinated beef strips, cook until browned and cooked through, about 5-6 minutes.
5. Pour in remaining marinade and cook for another 2 minutes to thicken the sauce.
6. Serve hot over cooked rice if desired.