The dimmer-switch approach is the dumb, simple version. If you're willing to fiddle a bit at first to find the right setting and afterwords never change it again it will work perfectly well.
The next step up would be a thermostat controlling a relay to turn it on and off. The thermostat will turn the relay on at some low set point, and back off at some high set point.
The last, "smartest", option would be a controller with a thermocouple in the oven and a electronically variable resistor controller the dimmer pack. If I were to do it I'd probably use a thermocouple, a PID temp controller from automation direct, and a hot-wired dimmer switch or some other dimmer pack.
These solutions obviously get progressively more expensive, with the PID coming in at probably around $200-300.