If using filet mignon, follow same instructions as chicken in Steps 1 and 4, cooking until filets reach minimum internal temperature, 5-8 minutes per side. Rest, 3 minutes.
If using tuna, follow same instructions as chicken in Steps 1 and 4, cooking until tuna reaches minimum internal temperature, 4-5 minutes per side. Tuna is often enjoyed medium-rare (pink in the middle). For medium-rare, cook 1-2 minutes per side. Consuming raw or undercooked tuna may increase your risk for food-borne illness.