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

Example Input: I know it's completely basic, but I've been reading up on alternative ways to make chicken wings (admittedly because I've been trying to find a similar recipe to Korean soy garlic chicken) and I came across this recipe from Momofukufor2.It mentions rendered chicken fat, and I'm not exactly sure what that meant. I'm familiar with twice fried wings, so is this just another way of saying "the oil you cooked the wings the first time around"?
Example Output: What is "rendered chicken fat"?

Example Input: Recently watch a cooking show, and in one of the recipes (before cooking the chicken) the instruction was to put the spice below the skin of the chicken.How to do it? Does it have some special methods to preserve the quality?
Example Output: How to stuff and/or spice the chicken BELOW the skin?

Example Input: I understand that food cooks differently in a double-boiler than when cooked "directly" - but don't know why that is.How does utilizing a double-boiler change how food cooks?
Example Output:
Why does food cook differently in a double-boiler?