In a mixing bowl, whisk together egg yolks, sugar, brown sugar, salt and about ¼ cup of the half & half.
Combine the cream, remaining half & half and milk powder in a large (2-3 quart) saucepan and heat, watching carefully, until it starts to boil. Keep a close eye on it because the milk powder will cause the mixture to boil over if you don't catch it in time.
Before the milk mixture boils over, carefully whisk the hot cream mixture into yolk mixture. Return the mixture to the saucepan; whisk over medium-low heat until the temperature reaches just above 175°F. This should only take about 3 minutes. Pour the custard through a fine-mesh strainer into a bowl. Let cool for about 5 minutes.
Whisk in the bourbon and vanilla extract. Let the mixture cool enough so that you can refrigerate it, then cover loosely and refrigerate for about 8 hours or until very cold.
Churn according to the directions of your ice cream maker. Transfer to a the container of your choice (you can use a plastic tub, a loaf pan or disposable ice cream containers), then cover and chill for several hour or until firm.