You literally just heat up 6 yolks, some vanilla of choice, 150g (maybe 3/4 cups?) sugar in a double bath, whisk until creamy, add 300g cream (about 10 1/2 fluid ounces?) and like 150g rum (my preferred thing) or milk (roughly 0.6 cups?) and whist for 5 minutes.
Oh yeah, and let it cool or top with whipped cream and cinnamon and enjoy hot. feel free to use lactose free alternatives.