Given the background description of some cooking related query, summarize the question into a title

Input: Consider Input: When I see tuna steaks, seared rare, on restaurant menus it's almost always Ahi tuna specifically. What's special about Ahi with this preparation method? Does it have different cooking properties from other kinds of tuna steak, like Yellowfin? Or is it an economic matter?I ask partly out of curiosity and partly because I'd like to make this myself, so want to know if I should be preferring Ahi to other tunas that are sometimes at the fish market.

Output: What's special about ahi tuna?


Input: Consider Input: In Masterchef The Professionals (season 8 episode 11), Marcus Wareing demonstrates his skills test and cooks a burger. In the process, he rapidly cools the onions after sweating them by placing them on a freezing tray. Would it make a noticeable difference to skip that step? I never did this and my burgers did not fall apart as he suggests. Is there some other reason for doing this?You can see the episode here (skip to 17:30).

Output: Cooling cooked onions before adding to raw mince


Input: Consider Input: Every chocolate-based recipe I've seen either requires tempered chocolate or can use either tempered or untempered chocolate. Are there any recipes or techniques that specifically require untempered chocolate?EDIT: I think the question might be a little unclear. To clarify, I have a block of tempered chocolate; I use this to make cordials (must be tempered) and ganache (doesn't matter). Are there any uses for it where I'd have to untemper the chocolate first?


Output: Are there any situations where untempered chocolate is better than tempered?