Freeze the bowl of your ice cream maker for at least 12 hours, until frozen solid according to manufactures instructions.
Add the brown sugar and butter to a medium sauce pot over medium heat and stir constantly until the butter is melted, and the sugar starts to dissolve. 3/4 cup brown sugar, 1/4 up unsalted butter
Add 1 cup of the cream, milk, to the pot and heat it until the edges start to bubble. 2 cups heavy cream, 1 cup whole milk
In a large bowl, whisk the egg yolks for a couple of minutes until they start to lighten in color. 5 egg yolks
Slowly pour 1/2 cup of your cream mixture into your egg yolks while whisking vigorously. Pour another 1 cup of your cream mixture, 1/2 cup at a time while whisking the whole time.
Pour the egg mixture back into the sauce pan with the remaining cream mixture and continue to heat for another 5 minutes until the mixture is thickened a bit.
Pour the custard mixture through a strainer into another large bowl. Add in the remaining cup of heavy cream, vanilla extract, and salt and stir it all together. 1 tsp vanilla, 1/2 tsp salt
Put the bowl into an ice bath and allow to set for about 15 minutes, stirring occasionally.
Cover the bowl and place it in the fridge for about 2 hours, up to overnight.
Pour the custard mix into a prepared 2QT ice cream maker and run it for about 25 to 30 minutes, according to manufactures directions, until it is like a soft serve consistency.
Scoop the ice cream into a 2QT container, and cover it with a lid, or plastic wrap and foil.
Place it in the freezer for at least 6 hours, or until frozen solid enough to scoop.