A cooktop appliance and heating element, as provided herein may define a heating zone having a thermostat positioned therein. The thermostat may include a base, a bimetallic disk, and a conductive spring. The base may extend axially between a first end and a second end. The bimetallic disk may be disposed within the base. The conductive spring may be disposed within the base in biased engagement with the bimetallic disk to motivate the bimetallic disk towards the first end within the base. The conductive spring may include a first layer and a second layer. The first layer may extend from a contact end proximal to the bimetallic disk to a joinder end connected to the first terminal. The second layer may extend from a biasing end proximal to the bimetallic disk to a secured end fixed within the base.