This is a question I've been wondering about for a while as a home baker and amateur food scientist. Why do recipes for whipped, fluffy desert components like whipped cream or buttercream icing always seem to call for powdered sugar? If I want to add sugar to a something, why would I also want to add the anti-caking agent (usually starch I think) for powdered sugar as well? Is that starch actually something beneficial for a whipped desert? Because as far as I can tell, the only time powdered sugar makes sense is when it's dusted on top of something or incorporated into a desert that is being mixed by hand and doesn't have the shear of a mixer to dissolve or emulsify the granulated sugar. And I've never had any issues just using regular granulated sugar and honestly prefer it to powdered sugar for icings, whipped cream and the like. If a recipe calls for powdered sugar, but it's being combined with a mixer or beaters I just use regular sugar and the results are great.

Anyone have any thoughts or experience as to what I'm overlooking? Or is it just a hold over from a time when electric mixers weren't common and you needed a finer sugar to incorporate the sugar by hand?

There are many tips or techniques that are strongly recommended for cooking, but it's hard to know which are evidence based and which are just passed along because that's what people always do.

Which are the tips that need more evidence?

Here are two that I struggle with, about stainless steel pans:

1. Water drop test / leidenfrost

People say that if you get your pan hot enough to get the leidenfrost effect and then add the oil you'll have less problems with sticking. My problem with this is that it means the pan gets very very hot - much hotter than it needs to be for most uses. My other problem is they all say "Look, I'll cook eggs and they won't stick" and those videos either have a ton of cuts, or the eggs stick and you can see the person pushing with a spatula to get rid of the stick, or their "scrambled eggs" is really a chopped omelette.

2. Heat the pan before adding oil. I don't understand this. Again, people say it helps prevent sticking, but they use some argument about "pores" which just feels hokey. I add cold oil to a cold pan and bring it up to temperature before adding food so the pan and oil are both at the right temperature, and food sticks and then releases, because that's how stainless pans work.

I'm aware I could be completely wrong here and that there may be a good evidence base for these, but they don't seem to work based on how I cook.