Check Engine Light On problems of the 2011 BMW Z4

The car stalled for the first time. I was driving for about 5 minutes at around 25-35 mph and made a stop at a traffic light. While at a complete stop, the car engine and all the electrical shut off completely while in gear. I put the car into 'park' then tried to restart. It did not start the engine but the electrical came back on and the yellow check engine light appeared. After two attempts (taking key out, putting key in, and starting the engine), the car starts again and everything went back to normal.