I doubled it and used a whole can of pumpkin which worked quite well, i also used 2 cups of sugar instead of 2.5, and I used aquafaba for eggs instead. Also I'm not sure why it says fill the cups 2/3, I filled them full and it worked well; these don't rise much in the oven. Turned out great, my pumpkin chocolate chip muffin craving is satisfied :)
