If you want to do this on the cheap, see if you can find an old C-band mesh satellite dish. They can be found for free in rural areas of the US and Canada where people have them rotting in their yard. Like so:

http://www.vk3nro.com/122East2014/CBandDish.png

Cover in aluminum foil or mylar or whatever is cheap and highly reflective. Cook food at the location of the feed focus.