Making a solar tracker for a solar cooker or solar panels is easier than you may think. You could design one that uses a micro-controller or complex circuit. But, it can also be done with JUST small solar panels and a DC motor.
The concept is simple. You have two or four small identical panels that are each powerful enough to spin a small DC motor. There is a divider between the panels that cast a shadow when the unit is not pointing directly at the sun. The panel that doesn't have a shadow cast on it produces all the power and turns the motor. As the shadow starts to minimize, the other side's panel starts applying reverse current to the motor and slowing it down.
You could have more than one panel each side, as shown below.
Something to remember is that the motor will have to be geared down so the output is lower. Or you can find a geared motor, such as a windshield wiper motor. You could also use a smaller motor and just use a string wrapped several times around the spindle or capstan of the motor. The rest of the string would wrap around a wooden pulley or disk from both sides. And, of course, the string would be stretched taut.