Line an 8 inch square pan with foil and spray the foil with cooking spray. Alternatively, butter the pan.
In a large 3 quart saucepan, combine sugar, cocoa, milk, cream, corn syrup and butter. Cook over medium heat, stirring until mixture comes to a boil. Cook to 238F on candy thermometer (soft ball stage). Do not stir. Remove from heat. Do not stir.
Cool to 120°F Add brandy. Beat until mixture starts to lose its gloss. Quickly pour into greased pan.