1. Whisk together first 3 ingredients in a large heavy saucepan. Gradually whisk in milk and cream. Cook over medium heat, stirring constantly, 10 to 12 minutes or until mixture thickens slightly. Remove from heat.
2. Whisk egg yolk until slightly thickened. Gradually whisk about 1 cup hot cream mixture into yolk. Add yolk mixture to remaining cream mixture, whisking constantly. Whisk in vanilla bean paste. Cool 1 hour, stirring occasionally.
3. Place plastic wrap directly on cream mixture, and chill 8 to 24 hours.
4. Pour mixture into freezer container of a 1 1/2-qt. electric ice-cream maker, and freeze according to manufacturer's instructions. (Instructions and time may vary.)
*Vanilla extract may be substituted.
Try these twists!
Chocolate-Raspberry Ice Cream: Before transferring ice cream to a container for further freezing, stir in 4 oz. finely chopped semisweet chocolate, and gently fold in 1/4 cup melted seedless raspberry preserves.
Coconut Cream Pie Ice Cream: Reduce milk to 1 cup. Stir 1 cup coconut milk into sugar mixture with milk. Before transferring ice cream to a container for further freezing, stir in 3/4 cup toasted, sweetened flaked coconut.