Mountain Laurel Designs’ Titanium Mug has to come close to winning the prize at 39 grams for a 475 ml mug which is at least sturdy enough to carry around without its crushing. I would recommend this for ultralight overnight trips such as an ultralight hunter might undertake, for example. You could cook a simple meal in it such as two minute noodles combined with a cup-a-soup. A similar pot is Toaks 550 ml handl-less at 43 grams.
You might combine it with an egg-ring stove (http://www.theultralighthiker.com/the-egg-ring-ultralight-wood-burner-stove/) from 12.5 grams, and a titanium windscreen (https://www.toaksoutdoor.com/products/wsc) 14 grams for a total cookset weight of 65.5 grams
I have boiled a cup of water (on a 13 gram esbit stove), made coffee and drunk it from a 375 ml beer can I had cut the lid out of with a can opener. You need something to insulate it, perhaps a large rubber band fashioned from a cycle inner tube, but it works and is extraordinarily light.
Trail Designs offer a Caldera set-up which utilizes a large Heineken can as the cookpot, but again it needs a plastic jar to protect it from crushing, so you have to be very careful: https://www.traildesigns.com/products/caldera-keg-f-stove-system The weight of the pot + cone + stove is 77 grams!
If you want to cook a substantial meal and have a set-up which is pretty near indestructible in your pack, this Toaks pot at 146 grams including the frypan lid is hard to beat: https://www.traildesigns.com/products/toaks-titanium-1100ml-pot-ckw1100 I have a one piece titanium cone (also from Trail Designs) which fits inside it perfectly so that I can cook with an alcohol stove or esbit or with a small wood fire. It also works with the Evernew 900 ml pot at 123 grams including frypan lid: http://www.theultralighthiker.com/cookset-woes/