Whisk the yolks, cornstarch, and the 40 grams sugar in a medium bowl; the mixture will be very thick, but try to whisk enough to remove most of the lumps.
Put the 75 grams sugar in a medium saucepan
and cook over medium heat until dark brown; don't worry if it crystallizes a bit. Turn the heat to low and whisk in the maple syrup
, then whisk in the whisky, turn up the heat, and let simmer for 1 to 2 minutes to boil off the alcohol
Whisk the milk
and vanilla bean
scrapings into the caramel
mixture and bring to simmer
. Slowly whisk about half of the hot mixture into the yolks, then whisk that mixture back into the pot, bring to a boil, whisking, and cook, still whisking, until thickened. Remove from the heat and whisk in the butter, salt and maple extract. Pour into a shallow dish, press plastic wrap
onto the surface, and chill until set and very cold, about 4 hours.
Beat the cold pastry cream in a standing mixer
until smooth. When ready to use, whip
the cream until it is very stiff, then beat into the pastry cream. Chill until ready to use.