The pilot stated that after taking off at night, he raised the landing gear, started a turn to the outbound heading and adjusted both propeller controls. He then turned on the overhead light, adjusted the heat by moving both selector levers to the center position, continued climbing and had started to adjust the mixture controls, when ATC gave him a frequency change. At that time, both engines lost power without warning. He declared an emergency and tried to restart the engines, but was unable. He said he then 'cut' the mixture controls and made an emergency wheels up landing in a field. The airplane was substantially damaged. An investigation showed there was sufficient fuel with no contaminates. Fuel flow was established from the fuel tank(s) to the fuel control unit(s) by using the electric fuel pump. The left engine was started and test run with no anomalies noted. The right engine could not be run due to its unsafe condition, but an exam of the engine revealed no anomalies.