Okay kiddo, have you ever had soup or stew before? Well, when you make those things, you have to cook all the ingredients together in a pot, right? Double steaming is when you want to cook something extra gently and slowly, so you put it in a smaller pot or dish, and then put that small pot inside a bigger pot with some water in it.
Why do we do this? Well, sometimes when we cook things in a regular pot, they can get too hot and break down or become mushy. But with double steaming, the water in the big pot helps regulate the heat and keeps things from getting too hot. Plus, since the small pot is covered, all the steam gets trapped inside and helps cook the food even more evenly.
So it's like cooking food inside of its own little sauna, and it comes out super tender and flavorful. Some things you might want to double steam are vegetables, seafood, or even desserts like custard. It takes a bit longer than regular cooking but it's worth it for the delicious results!