While Nick's idea was good, major supermarkets already have it as part of their framework.
Take Tesco for example. They have a website named Real Food (or something like that) with recipes and if you like the look of one recipe, you can click on 'get all ingredients' at bottom of the recipe. This would take you to Tesco's own site with a list of ingredients in already one place for you to select all - or some if you already have certain ingredients in your stock - that you'd like to buy. You can then add whatever else you want to that shopping list. Once done, pay for it and Tesco will deliver the lot the next day at a time of your choosing.
I think Nick's idea may be a tad old for some. Plus, most food suppliers prefer to have it as part of their frameworks. Also there's something like Ocado, which collates ingredients from suppliers for a customer's shopping list and deliver. So Nick's software idea needs to be unique to overcome those existing patents.
I think he's missing an opportunity to focus on an idea of having a shopper using own mobile phone to scan a bar code of the main ingredient and this would bring up a list of recipes on spot. Shopper can then shop for other ingredients listed in their selected recipe.
Sorry, waffling about nothing.