Hi.
You should check the oven sensor and it's connector plug.
At room temperature the resistance should be about 1100ohm.
Replace if needed
Part number: 9782081 
If the sensor is OK - replace the control board
Part number: 9754383 
Here are the breakdown diagrams and
Control Panel parts for Whirlpool KESC307HWW6 - AppliancePartsPros.com
Post the results.
Simon.