I found other threads with this request, but they have all been closed, so I can't add my +1
I use the recipes feature a lot, and being able to duplicate an existing recipe would save me a lot of time.
For example, I eat breakfast burritos almost every morning, but I make lots of different versions that vary by one or two ingredients. I'll eat several variations in the same week, so just updating the recipe every time I add it to my food log isn't a good option.
This would also help when I'm making a one-time change to a recipe (say, if I don't have the right amount of chicken on hand), and don't want to forget what the original recipe calls for.
Maybe this would make a good premium feature?