My experience with the function is limited, but I think it’s decent. Markdown support, import from websites etc. If you add the items to the recipe with their amounts and then write them out in the text it automatically give you the amount you need based on the portions specified.
On app.kitchenowl.org you can create a demo-user and household. Within that, you can try the recipe function. Sign up requires a mail-address, but it does not need to be a valid one.
To be fair, the game’s rated 18+ in the UK. In terms of the law, this probably doesn’t suffice. But theoretically, there still is a kind of age-check in place :'D