Bests & Worsts Reviews from Amazon

I'm having a terrible time. I have cooked three times, three different things, three different time and temperature settings. Each time the food was burned on the outside and cool (or warm) on the inside. I cannot cook for the required time at any temperature. A cook time of 30 min. at 350 degree was burning at ten minutes time. Similar results for other attempts such as baked potatoes and pancakes. Burnt!! I believe the temperature is off by a considerable amount and I'm buying an oven thermometer to check it out.