I haven't seen this feature requested yet, but it's one that I've been wanting for quite some time.
One of the things that I find most annoying about using the site/app is the lack of an ability to 'save' multiple recipes to one clean shopping list, with quantities, ideally organized by grocery section (e.g. "flours/grains", "dairy", "proteins", "vegetables") and with the ability to check things off depending on what I already have in my pantry or I've had to order online. This is obviously especially true when one is cooking three-course meals (or more!) off the site.
I don't find either the app or the site to be particularly fast (it doesn't bother me outside of this context), and the app doesn't save searches or sessions that I've experienced. So every time I switch to a different recipe, I have to go back to the first recipe, scroll over to the second page, put that one ingredient in my physical shopping cart, and then go back to the second recipe, scroll over, and repeat section by section until insanity ensues, usually after I've gotten home and realized I missed a keystone ingredient from one of the recipes and can no longer make it or have to sacrifice another 30 minutes to go to the store again.
It's true that I could copy and paste to a different app or make a physical grocery list, but I'm an old and lazy curmudgeon and we are people too.
cs4life,
bk