Mix the steak marinade ingredients together well.
Place the piece of flank steak in a roomy container with a lid, and pour the marinade over it. Flip it to make sure all parts of the meat get covered.
Place container in the fridge for 1-2 hours or more to fully marinate.
After it's finished marinating, heat a bit of olive oil on a skillet at medium high heat and cook the steak for 4-5 mins on each side. Use a meat thermometer to check in on the internal temperature until it reaches about 130-135°F for a medium rare steak.
Once it finishes cooking, place it on a cutting board and let it rest for 5-8 mins. Slice into thin slices against the grain before serving.