The flavor of Tuna is enhanced and the fat gets sweeter by searing. You can use a blowtorch or it is easy enough to lightly sear both sides of the fillet on frying pan. The center should be kept rare.
Seared Tuna Steak
1 Sashimi quality Tuna block
2t Salad oil
1. Salt and pepper on Tuna
2. Pre-heat frying pan hot and grill both sides of the block of Tuna
3. Take out while the center is rare.