In Hawaii, for instance, Ahi tuna is a prevalent addition to local blends. Ultimately, the type of fish won't make such a huge difference as an ice cream topping, so just go with your favorite.

Add the cream and simmer until reduced by half, 15 minutes. Strain the sauce, season with salt and pepper; keep warm. 2. Season the tuna with salt and pepper and coat both sides with the sesame seeds.