1. Preheat oven to 350�F. In a large bowl, mix together flour, sugar, cocoa, baking soda, and salt. Whisk in oil, vinegar, 1 tsp vanilla, and 2 cups cold water until well blended
. 2. Pour into 2 greased 23 cm round cake pans, dividing evenly. Bake 25 to 28 mins, or until a cake tester inserted in center comes out clean. Let cakes cool in pans 15 to 20 mins, then unmold onto racks to cool completely
. 3. Meanwhile, in a 2 litre bowl, combine cream, semisweet chocolate chips and milk chocolate chips. Heat in a microwave on High 1.5 to 2 mins, or until melted and smooth when stirred. Stir in remaining 1 tsp vanilla
. 4. Remove 0.75 cup chocolate mixture and set aside to cool. While remaining mixture is still warm --but not hot --add Snickers pieces and stir until combined (some pieces will remain chunky; some will melt). Set aside to cool
. 5. When firm enough to spread, fill stacked cake layers with half of Snickers mixture. Spread remaining mixture evenly over top of cake. Frost sides with some of reserved 0.75 cup chocolate mixture and spread remaining chocolate mixture over top of cake. Sprinkle peanuts around top edge of cake to make a border. Refrigerate for at least 1 hour before serving.