Cream together butter, powdered sugar, salt and rum flavoring. Stir in hot milk, beat until creamy and smooth. Combine brown sugar, butter, milk and corn syrup. Cook, stirring occasionally, until mixture reaches firm ball stage (248-250). Pour over first mixture, beating until smooth and thick. Pour out on buttered platter. When set and easily handled, knead in the chopped hazelnuts and form two rolls. Chill. Heat caramels with water in top of double boiler. Spread caramel mixture on top side of roll. Press on sliced hazelnuts. Turn roll over, spread with more caramel and sliced hazelnuts. Repeat process for other roll. Chill and slice.

Industry and The Hazelnut Marketing Board