First make 1 pint creme anglaise: Heat to a simmer 1 pt. half and half and 1/2 cup sugar. In a bowl, whisk 3 yolks.Mix 1/3 of the hot liquid with the yolks, whisking. This warms the yolks. Now whisk the yolk mixture back into the hot liquid OFF THE FLAME. Let cool.When cool, add flavoring: 1/4 cup dark rum 2 ripe Haas avocadoes, pureed juice and zest of one lime. Freeze in an ice cream freezer according to the manufacturer's instructions.