To make the hot chocolate: Pour the milk, amaretto and sugar into a medium-sized saucepan and place over medium heat until the milk comes to a near simmer, stirring until the sugar dissolves. Place the chopped chocolate in a bowl. While the milk is heating up and before it comes to a near simmer, set the bowl of chopped chocolate over the saucepan of milk, stirring until the chocolate is melted and smooth. Whisk the melted chocolate into the milk mixture to blend, and keep warm.

Arrange all the berries in a single layer on a baking sheet, making sure they are well spaced apart. Cover with plastic wrap and freeze for 2 hours or until the berries are frozen.

Meanwhile, place the cream in a heavy medium saucepan. Using a small sharp knife, scrape the seeds from the vanilla bean into the cream. Add the bean to the cream. Bring the cream to just below simmering over medium heat.

Place the chocolate in a bowl and pour the hot cream mixture over the chocolate. Discard the vanilla bean. Let stand for 5 minutes to allow the chocolate to melt slightly, then stir the cream mixture until the chocolate has melted completely and the sauce is smooth.

Arrange the berries on a serving platter or in individual bowls and pour the hot sauce over the frozen berries. Serve at once.