In a large heavy saucepan, combine cream, milk, sugar and salt. Split vanilla bean in half lengthwise. With a sharp knife, scrape seeds into pan; add bean. Heat cream mixture over medium heat until bubbles form around sides of pan, stirring to dissolve sugar. , In a small bowl, whisk a small amount of the hot mixture into the egg yolks; return all to the pan, whisking constantly. Cook over low heat until mixture is just thick enough to coat a metal spoon and temperature reaches 180°, stirring constantly. Do not allow to boil. Immediately transfer to a bowl. , Place bowl in a pan of ice water. Stir gently and occasionally for 2 minutes; discard vanilla bean. Press waxed paper onto surface of mixture. Refrigerate several hours or overnight., Fill cylinder of ice cream maker two-thirds full; freeze according to the manufacturer’s directions. (Refrigerate remaining mixture until ready to freeze.) Transfer ice cream to a freezer container; freeze until firm, 4-6 hours. Repeat with remaining mixture.