I remember my mom making this but she used a creme anglaise type of sauce. I don't know if it was a real creme anglaise but I suspect she used something very close. She used to be a chef for major companies and armed services in the NWT and Co. in America and if she could cut corners but give the same result she would go that route. A liquid vanilla pudding?
Anyways, that's the way I prefer my pudding, and I suspect, since I have not had the rum sauce it would be not as sweet.