this is the one I use but a packet of it comes in pretty much every box of Mac & Cheese.
I use this kind of powder so my Mac & Cheese sauce can have however much flavor I want (and be on any kind of pasta or veggies that I want)! And only 25 cals per tablespoon which is more than enough to season popcorn. It does anything popcorn seasoning can do plus makes a bomb sauce!