Is she cooking from one app/format that could be projected easily? When using a resource like that, I usually cook from a mixture of books, blogs, recipe sites and so on. It would be too difficult to get that info put onto a clearly readable display IMO. Sometimes they're lists, sometimes they're fragments of info in image captions, or in a story.
I suspect sound is probably a much better approach. A good speaker + microphone and you can intuitively do things like set 30 minute timers as you put something in the oven. Or just get a quick rehash of the next steps. "Finished kneading bread, now what?"
Also, a single recipe is fairly easy to follow, handling a few a the same time is where a computer could actually be useful.
I have posted here before about an app that helps you schedule a set of recipes so that things are ready in sequence. It would show you what can be prepared in advance, what needs to be done just before plating, etc. A recipe Gantt chart.
I could also make use of a touchscreen splashback showing either general entertainment or recipes where I could strike off ingredients or steps as they were completed. Saves having the iPad or a book taking up bench space.
Could have touchscreen in one area and then display with heat-resistant glass behind the cooktop. Maybe in 10 years time.