1Whisk the egg yolks with the sugar in a large bowl. In a nonaluminum saucepan, combine the milk, heavy cream, and licorice and bring to a boil over medium-high heat, stirring frequently so the licorice melts. (If the licorice resists melting, purée it with some hot milk.)
2Beat a little of the hot milk mixture into the eggs and then, in a steady stream, slowly whisk in the rest of the hot milk. Return the mixture to a pan over medium-low heat and cook, stirring constantly, until it thickens visibly and registers 165°F on a candy thermometer. Do not boil.
3Remove from the heat and stir in the Pernod liqueur and vanilla extract. Strain through a fine sieve into a bowl, discarding any solids. Cool, then chill in the refrigerator. Freeze as directed in an ice cream maker.
Beverage pairing: Cocchi Barolo Chinato, Italy. The sharp flavor of licorice is best confronted head-on with a small dram of this wine-based, fortified liqueur from the Piedmont region of Italy. Flavored with herbs, roots, and quinine, this digestivo will make a nice counterpart to the ice cream.