Heat the cream, half and half, and candy caps until steaming and cool.
Meanwhile, bring the maple syrup and brandy to a boil and cook for two minutes on high, then pour into a mixing bowl and allow to cool for a few minutes.
While the syrup is still warm, beat it with the egg yolks until light in color.
Whisk ⅓ of the cream mixture into the egg yolk-maple mix, then whisk in the rest. Transfer the mixture back to a saucepan and cook on low heat, stirring constantly with a spoon, until the mixture barely coats the back of a spoon, about 15 minutes. You can also cook the sauce in a double boiler above a pot of simmering water, which is easier if you haven't worked with custards before.
It’s important to take your time cooking the crème anglaise, as if the heat gets too hot it will curdle the yolks and make the sauce chunky. Even if you do curdle the yolks though, you can strain it and it will be ok. Chill the sauce completely before serving to give it time to thicken. If you're in a pinch, stir it over a pan of ice.