Freeze the ice cream maker drum in the freezer at least 24 hours prior to churning your ice cream.
In a medium saucepan, heat the milk, cream, 50 grams of sugar, and a pinch of salt, along with the vanilla bean (split, seeds scraped into the pan of milk). Heat it on medium til it comes to a simmer, then take it off the heat and let it steep for about 30 minutes.
Meanwhile, whisk the egg yolks with 50 grams of sugar til they have lightened in color. Prepare a bowl with a strainer and set it next to the stove.
Bring the milk mixture back up to a simmer, then temper the eggs with half the milk mixture, and pour it all back into the pan.
Stir the mixture with a wooden spoon on medium heat til it coats the back of a spoon (à la nappe). You will know the custard is done cooking when you give the mixture a stir, and it stops moving right away (unlike fluid milk that would keep swirling around the pan). Immediately take the pan off the heat and strain the custard into the bowl you set aside. Cover with plastic wrap and chill in the freezer for about 30 minutes, then transfer the bowl to the fridge to chill overnight.
To prepare the boozy cherries, heat the halved cherries with the sugar and water on medium heat for about 10–15 minutes, til the juices have thickened. Take it off the heat, add the bourbon, and transfer to a container to chill in the fridge over night.
When your ice cream drum, custard, and cherries have all chilled overnight, churn the ice cream (according to your machine’s instruction booklet). I let mine churn for at least 15 minutes til it’s really thick. You can add the cherries towards the end, or swirl it on top of the ice cream, directly in the container you will be storing your ice cream in. When the ice cream is made, immediately transfer it to a container and get it into the freezer.
Homemade ice creams set very hard. Take it out of the freezer for about 10 minutes or so before serving.