In a large heavy saucepan, heat the milk, cream, sugars and salt until bubbles form around sides of pan. Whisk a small amount of hot mixture into the eggs. Return all to the pan, whisking constantly.
Cook and stir over low heat until mixture is thickened and coats the back of a spoon. Quickly transfer to a bowl; place in ice water and stir for 2 minutes. Stir vanilla. Press waxed paper onto surface of custard. Refrigerate for several hours or overnight.
In a small skillet, saute pecans in butter, stirring constantly. Cool.
Fill cylinder of ice cream freezer two-thirds full; freeze according to the manufacturer’s directions. Stir in toasted pecans. Refrigerate remaining mixture until ready to freeze. When ice cream is frozen, transfer to a freezer container; freeze for 2-4 hours before serving.