If you have to stand there stirring for an hour, you have to. Do not use ceramic pots as they will hold the heat for too long and may give rise to burns. This is due to the caramels forming from the sugar. It will also thicken. Keep stirring the bottom to prevent the bottom from burning.
Burns spoil the kaya taste.
If possible, lower the flame even more. After it has cooled, you can bottle it in jars and refrigerate. This stuff can last for 3 days in room temperature, that is before the ants get to it. I had better success using freshly squeezed coconut milk than the canned or packed ones. Do not adulterate this recipe by adding additional flavorings.