iOS: Chances are that your oven only has one timer. Even if you add in your phone, that still only equals two timers. For those more complicated meals where multiple elements are involved, you need more than that. Thyme is an app that gives you five separate timers: one for each hotplate plus the oven itself.
Open up Thyme and you get an image of a oven. Here, you can set a timer for each individual hotplate as well as the oven. Just tap the part you want to set the timer for and drag your finger to the right time. The app doesn't have any options for special sounds or alerts, but it gets the job done and makes those complicated meals a little bit easier.
Thyme (Free) [iTunes App Store]