Caramel: In a small, heavy saucepan combine the sugar and the water. Be sure all sugar granules are washed down from pot sides (you can use a pastry brush dipped in water to brush down the sides). Cook over moderate heat, swirling the pan occasionally, until color is golden brown and the mixture smells like caramel. This will take about 10 to 15 minutes. When it is a deep golden color, plunge the bottom of the pot into cold water to immediately stop the cooking (otherwise the heat of the caramel will keep it cooking long after you remove it from the heat, and it could burn). Immediately and with great care, pour the hot caramel onto a large sheet of greased parchment paper on top of a baking sheet. Set aside until cool, then crack into 1/2inch pieces.
Ice cream: Combine cream and half-and-half in a medium, heavy saucepan. Bring to a boil.
In a large bowl, whisk together egg yolks and sugar until thick and pale yellow. Pour in the boiling liquid and stir until combined. Stir in the vanilla. Strain into a large container and refrigerate until cold, or place in a bowl nested in a larger bowl of iced water and stir occasionally until cold. Stir in the Crema. Pour into an ice cream maker and process according to the manufacturers instructions. When ice cream is done, fold in the reserved caramel pieces. Store in freezer 1 to 2 days.
In large bowl whisk together cream and buttermilk. Cover and set in a warm place (a gas oven with just the heat from the pilot light for example) for 8 hours. Place in refrigerator. Can be kept for up to a week.
c.1997, M.S. Milliken & S. Feniger, all rights reserved