1. Line a loaf pan (about 9" X 5") or small square pan with parchment paper, allowing paper to hang halfway over the sides of the pan. 

2. In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl, add the marshmallow cream, chopped semisweet chocolate, 1/2 teaspoon vanilla extract and 1/4 teaspoon Bourbon Flavor. Mix together and set aside. 

3. In a heavy, 2-quart saucepan melt the butter over low heat. Stir in the brown sugar, granulated sugar, and whipping cream. Increase heat to medium and bring mixture to a boil WITHOUT STIRRING. Wash down the sides of the pan with a wet pastry brush to remove any stray sugar crystals clinging to the side of the pan. 

4. Clip on a candy thermometer and continue to cook, WITHOUT STIRRING, to 240° F. Remove from heat and allow the mixture to cool until no longer boiling. 

5. Pour the hot mixture into the bowl that contains the marshmallow cream mixture and stir until well combined. 

6. Using a spatula, transfer candy to the lined pan and spread to smooth. Sprinkle top of fudge with the toffee bits and milk chocolate chips, pressing slightly to adhere. Once firm, cut fudge into slabs or pieces. 

Makes about 2 pounds of fudge