The rocket stove oven here was a combination of a wall oven bought second hand from refuse centre and a rocket stove made from a steel box section. We insulated the stove itself with a clay and sawdust mix, finished with a clay and news paper pulp mix for a smooth result. The oven’s temperature is controlled by the amount of wood burning at the time and once mastered can be used as well as any oven. Just insert a sugar thermometer for example and you’ll be good!
Other designs have been done by lots of people, for example a rocket stove pizza oven is simple enough to build and saves on the fuel compared to a traditional one! See the following links for more ideas on rocket stove ovens. Enjoy!