What punishment should I recommend for Soldier who showed up for an ASU inspection with it on a hanger?

You should have made her go and put it on at once. Does the Army no longer have height and weight requirements?

If you knew she didn't fit into her uniform a month ago, where was your follow up prior to inspection? I suspect the leadership is partly at fault here.

Having her buy a new uniform and stand watch consequential shifts might ring the bell, oh don't forget to get the receipt !

She really needs some additional training. That might catch a few wisps of wind in the civilian world, but it shows an attitude that really needs a swift adjustment. So, corrective action would include appropriate treatment to drive home the concept of personal responsibility. Not to mention some challenging exercises to regain fitness. My 1957-1979 experience would prompt me to recommend more drastic measures, but I'm getting mellow.

As a leader, YOU should have noticed a member's physical change (weight gain) and YOU must take your role in that into consideration when assigning corrective action. You can choose to be punitive (not mandatory) or you can choose to build your member up. You don't have to coddle the soldier, but every member is an investment. It's a leaders job to get the maximum return on the investment even if that takes some time away from primary duties while the member receives nutritional counseling or physical conditioning and coaching at the fitness center. There could even be underlying psychological reasons for weight gain. Ask yourself, "Is this soldier worth retaining?" And take the appropriate humane course of action.

Summary article 15 for failure to report in the correct uniform. You certainly can use nonjudicial punishment in this case. Or you could do corrective training by having them report in a different uniform every 15 minutes for a couple hours to make sure everything fits and they know how to properly wear it and how to correctly report to formation

You can't punish her nor can you force her to buy a new ASU. If she is with in regulation for H/W/T but the uniform no longer fits then she needs to go to supply and request a new uniform. A good leader would work with her to get her weight under control rather than immediately jump to punishment. You are supposed to mentor her and help her become a better soldier. Don't let your rank go to your head and forget where you came from. Help her help herself. If you can not do that then perhaps you should not be in a position of leadership. I've been in the army far too long and have seen far too many good soldiers go out because of poor leadership and I (myself included) have seen far too many soldiers get screwed over by "leadership".

Well... let's start with the first problem. Soldiers don't gain weight overnight. Does your unit have any sort of formalized monitoring. In my units we ran a inventory PFT every month, weigh-ins were part of the inventory. A gain in weight or a drop in PT performance should after 2-3 weigh-ins trigger the Chain of Command that trouble is coming down the track. A weight gain of 5-8% of total body weight is probably going to require uniform alterations. It appears the chain of command failed her.

Assumptions on my part...
1) There is no one between you and her in the chain of command.
2) She was not deliberately trying to piss you off.

I'd start with...
Explain this to me soldier.

If there is a valid reason (I'm having a hard time thinking of one.), deal with it in an appropriate manner and an appropriate timetable.

If there isn't a valid reason, same as above, deal with it in an appropriate manner and an appropriate time table. In addition, perform an official counseling. Without a significant awakening and a new found pro-active approach to a known problem, this soldier should not be promoted.

If my assumptions are not valid
_Counsel any leadership between you and the SPC. If the intermediate leadership is an NCO, make them come up with a solution and have them execute that solution. Also let that intermediate NCO leadership know that if they cannot carry the responsibilities of their leadership, admin reduction to a more appropriate rank and pay grade may be best for all.
_If she was deliberately trying to piss you off, make sure that she never again sees that as a desired outcome.

Simple. Extra duty, and get a uniform that fits. Unless she's a total balls up, UCMJ would only get in the way of purchasing a new uniform.

Honestly, I'm surprised she wasn't able to borrow a uniform from someone. No initiative.

Myself, I always liked to keep myself squared away and pretty much always made supernumerary.

After I returned from Vietnam and had gained some weight. I was underweight before that and We had an occasion not expected for the arrival of a Washington big shot We had to wear Class A blues, mine no longer fit. I had no idea until went to try it on that very day it no longer fit. Instead of standing out in the sun as We would have been doing Me and another guy in the same situation instead took a vehicle and went to a location across the other side of the runway to provide an observation there. The location was the Base Family Camp Recreational Vehicle area. We got to sit in the vehicle in the shade and had both restrooms and a small store with food and drinks next to us. They needed someone there but could in the process hide us as We both had to wear our short sleeve kaki uniforms instead of Class A Blue. No one gave either of us a hard time over that. Back then I was a Sgt and the other guy a SSgt. In the end run We had a lot better day than the guys in Class A Service dress. I did replace that uniform a quickly as I could after that experience and nobody gave us any grief over it.