The best part of preparing this steak is cutting it into a juicy steak roast. You don’t have to use a meat slicer to cut Costco tri-tip steak, so don’t be alarmed if you don’t know how. To do that, you need to find the center point where the two grains of meat run (they run in different directions) and cut the tri tip into thin slices, perpendicular to the grain of the meat. The meat will be more tender because of this. When you slice, keep your knife slightly angled.