NOTE: It is very important to follow these directions very carefully. It is also absolutely
essential to use a candy thermometer. Heat one cup of the butter in a large saucepan until
melted. Add the pecans and mix well. Bring to a boil and cook until the pecans begin to
change color. BE CAREFUL - this mixture will foam over so use a large saucepan. Add
the remaining one cup butter and mix well. This will cool the pecan mixture and stop the
cooking process. Remove from heat. Combine brown sugar, whipping cream and cinnamon
in a saucepan and mix well. Cook over low heat until blended, stirring constantly;
increase heat. Cook to 230 deg F on a candy thermometer. Stir in the pecan mixture, Add
sour cream and vanilla and mix well. Remove from heat.