Stir half-and-half and sugar in a medium-size saucepan over low heat until sugar dissolves. Add chocolate; stir over low heat until chocolate is melted and mixture is smooth. Remove from heat; stir in butter until melted. Stir in extract. Makes 2 cups.
Prepare chocolate fondue and pour into fondue pot, keeping the pot warm with sterno. Cut up fruit and pound cake into bite-size pieces. Arrange on a glass plate next to the fondue pot. Provide guests with dessert plates and fondue forks, allowing them to select fruit and cake to dip into the fondue using the forks provided.
Will keep up to 1 month in a tightly covered glass jar. To reheat, remove lid and place jar in a saucepan of simmering water. Stir occasionally until warm.