When making tuna steak, you want to cook the tuna long enough to develop a deliciously browned exterior but not so long that the lean, delicate fish dries out due to overcooking.

Whether you’re grilling, searing, or broiling your tuna, coating it in mayonnaise can insulate it and help it cook more gently while allowing the exterior to brown to perfection.

Mayo creates a fatty layer of insulation between the tuna and the heat, keeping it from overcooking. It gives you a greater margin of error when it's time to stop cooking the fish.

Another perk of mayo is its high-fat content. As the mayo-coated tuna cooks, the fat breaks down, and the Maillard reaction occurs swiftly, resulting in a tasty, browned exterior.

Hence, mayo doesn’t only make tuna steaks easier to cook, but it also makes them moist and tastier. Plus, most of the mayo gets cooked off, so it doesn’t add extra flavors, either.