1/2 c. white corn syrup
1 c. brown sugar
1/2 stick butter
1 tsp. vanilla
3/4 c. heavy cream

Combine corn syrup, brown sugar and butter in heavy saucepan. Bring to a boil. Boil gently about 5 minutes, stirring occasionally, until a candy thermometer reads 230 degrees. Remove from heat and add vanilla and stir vigorously for 1 minute. Let mixture cool to warm. Add the heavy cream, a little at a time, stirring vigorously after each addition to create a smooth, shiny sauce. Pour into hot, sterilized jars. Keeps, covered and refrigerated several months.