You really get two delicious desserts out of one recipe here--the ice cream and cookies make a delightful duo, but each can also stand alone. If you want to cut corners when serving the two together, the biscotti are just as good plain and not dipped in white chocolate.
Combine 2 1/4 cups whipping cream, evaporated milk, and sugar in a heavy saucepan over medium heat. Bring to a simmer, stirring occasionally; remove from heat. Gradually whisk about one-fourth of warm milk mixture into egg yolks; whisk into remaining hot mixture. Cook over low heat, stirring constantly, 5 to 7 minutes or until mixture coats the back of a spoon. Remove from heat; pour through a wire-mesh strainer into a large bowl. Stir in remaining 1 cup whipping cream, lemon rind, juice, and extract; cover and chill 1 hour.
Pour into freezer container of a 4-quart ice-cream maker. Freeze according to manufacturer's instructions. (Freezing instructions will vary among manufacturers.) Spoon ice cream into an airtight container, and freeze until firm. Serve with Ginger Biscotti.