Find a medium frying pan and set it on your range, set the element low-medium heat. If you are using a gas range maybe go a bit lower.
The trickiest part of french toast is the right temperature to use. Always err on the side of caution, in this case a lower temperature is what you need, you can always let it cook a little longer if you need to.
Keep in mind that the only ingredient which will actually needs cooking is the egg. Eggs don't need to be cooked to death, especially in such a thin layer. So keep that heat down!