Twist vanilla bean to release flavor. In medium stainless-steel saucepan heat milk and vanilla bean until just below simmering point. Remove from heat. Cover; let stand 20 minutes to allow vanilla to infuse milk.
For custard, in medium mixing bowl whisk to blend egg yolks and sugar. Slowly whisk in the hot milk; return milk mixture to saucepan. Cook over medium heat, stirring constantly with rubber spatula until custard thickens enough to coat back of spatula.
Strain custard through fine-mesh sieve into large heat-proof bowl placed in larger bowl of ice water. Stir custard until cooled. Return vanilla bean to custard. Stir in whipping cream, vanilla extract, and the 1 teaspoon kosher salt. Taste for flavor balance, adding additional salt or vanilla as desired. Cover and refrigerate until thoroughly chilled or up to 48 hours before freezing.
Remove vanilla bean. Transfer custard to ice cream canister. Freeze according to manufacturer instructions. Transfer ice cream to shallow glass dish. Cover with plastic wrap. Freeze to ripen before serving. Makes 12 (1/2 cup) servings.