Place the flank steak in a zip-lock bag. In the bag combine the minced shallot, soy sauce, olive oil, thyme, hot sauce and lemon juice. Freeze overnight. It should be thawed by the time it is needed.
When ready to prepare, remove flank steak from the marinade and place on a grill pan. Grill for about 3 or 4 minutes (for rare), or up to 5 minutes for medium.