A sesame seed-crusted, pan-seared tuna steak strikes the eyes and palate with a contrast of colors and textures. You have several options when it comes to flavoring a sesame seed crust. Add spices, such as smoked paprika; fresh herbs, like thyme; and lemon or lime zest to hit the sweet, sour and bitter notes, then tie everything together with some soy sauce for umami. But no matter how you mix the crust, pan-searing tuna only takes a couple minutes.
Add the sesame seeds to a mixing bowl. You need about 1/3 cup of seeds for each 8- to 10-ounce tuna steak.
Add kosher salt and freshly ground black pepper to the sesame seeds to taste. Add a pinch of salt and a crack of pepper, mix them together and taste to determine if you need to season the seeds more.
Add dried spices, freshly minced herbs and zest to the sesame seeds, if desired. Mix the seeds and other ingredients together using a whisk.
Spread the sesame seed mixture on a plate in an even layer. Coat the tuna steaks with a thin layer of oil on both sides and lay them in the sesame seeds. Lightly press on the tuna and turn each one over, then repeat.
Heat a couple tablespoons of oil in a pan over medium-high heat until wisps of smoke rise from it.
Lay the tuna steaks in the pan. Cook the tuna for about 2 minutes on each side for medium-rare, or until it reaches an internal temperature of 130 degrees Fahrenheit. Cook the tuna for 2 1/2 to 3 minutes for medium, or an internal temperature of 135 F.
Move the tuna steaks from the pan to a plate and serve as soon as possible. If you're slicing the tuna, let it rest for a few minutes so the crust sets.
The U.S. Department advises pregnant and nursing women, the elderly and children to only eat tuna steaks cooked to a minimum internal temperature of 145 F.