Heat the milk and vanilla bean in a medium saucepan set over medium heat until simmering, stirring occasionally with a heat-proof spatula. Meanwhile, vigorously whisk the egg yolks and sugar in a medium-sized bowl until the yolks lighten in color slightly.
Remove the milk from the heat and pour slowly into the egg yolks while whisking. Pour everything back into the saucepan, scraping the bowl.
Return the saucepan to the heat and, using a heat-proof spatula, stir until the mixture thickens slightly, approximately 3-4 minutes. Remove from the heat and discard the vanilla bean. Stir in the cream and vanilla extract. Allow to cool (I let it cool overnight).
Pour the mixture into an ice cream maker and prepare the gelato according to the manufacturer's instructions, until it's frozen and scoopable. Alternatively, place the mixture in a metal container and freeze, beating at 1-hour intervals, until the gelato is scoopable.