Bake 1- 13x9 " pan of brownies (double recipe so they are thick and cakey and add 1-2 extra eggs), cool for approximately 10 minutes.
Stir up chocolate frosting and add mini chocolate chips. Set aside.
Spread one container of marshmallow cream over brownies while they are still warm. Slightly melt frosting in microwave for approximately 20-30 seconds, stir and drizzle over marshmallow cream, run a butter knife gently through marshmallow and frosting mixture down one side and up the other to swirl the two together.
Sprinkle with chopped walnuts and toffee bars. If you place in the refrigerator for a few hours it will allow the brownies to be really dense and yummy and will make it a lot easier to cut apart. Happy baking!