Here are the parts. Note it is for a JKP56BA1BB no zero in the number.
Could not find any ifo using the given model number
Replacement parts for GE JKP56BA1BB | AppliancePartsPros.com

This repair is probably going to be a pain

Is it best to just replace the element or could the problem be something else?
Could be a number of things

1. The heating wire in the element is broken and is opening closing intermittently. You could try warming the oven up using the bake element.
Once warm try using the broil element to see it it now comes on all the time.
This may help isolate as a warm oven should not have much influence on the other possible causes.
Also pull the element, carefully inspect it and measure it with a meter usually around 20 ohms. Trouble is the problem is intermittent.
When it does heat up does it have a bright spot?

2. A loose connection between the element and the control board. Also check that wires are properly crimped to connectors.

3. The relay on the control board. Could be the contacts are just about shot. Could also be that there is an electronic problem and the relay is not being closed all the time. Either one requires replacement of the electronic oven control (EOC)

Be sure to unplug the unit when working on it, 240 volts is lethal!!!