step 1
Preheat oven to 320 degrees F (10 degrees C) and grease a 9-inch baking pan.
step 2
Add Powdered Confectioners Sugar (1 1/2 cups) to Thick Yogurt (1 1/2 cups), mix well.
step 3
Add Baking Powder (1/2 Tbsp), Baking Soda (1 tsp) and Salt (1 pinch). Mix, then let it rest for 5 minutes until you see a lot of air bubbles.
step 4
Add Vanilla Extract (1 tsp) and the Vegetable Oil (1/4 cup) and mix well.
step 5
Sift in All-Purpose Flour (2 1/2 cups) and Unsweetened Cocoa Powder (1/2 cup). Mix to form a smooth batter. Do not over mix.
step 6
Pour into prepared baking pan. Bake for 30 minutes or until the cake is fully cooked through. Let it cool completely.
step 7
For the caramel dark chocolate truffle frosting, add Granulated Sugar (1/2 cup) and Water (2 Tbsp) to a pan and let it come to a boil on lowest heat. Do not stir or the sugar will crystallize.
step 8
Once the sugar turns a light brown color, add two thirds of the Butter (2 Tbsp) and Cream (1/2 cup). Stir.
step 9
Pour caramel onto Dark Chocolate (3/4 cup) and let it sit for 5 minutes.
step 10
Stir well to combine. It should form a smooth ganache like sauce. Let it cool completely and refrigerate to get a thick truffle frosting.
step 11
For the chocolate mousse filling put Marshmallow (1/3 cup), Unsalted Butter (1 Tbsp), Dark Chocolate Chips (1/2 cup), and Water (1 Tbsp) in a heavy-based saucepan over medium heat.
step 12
Once everything is smooth and melted, remove from heat and let it cool a bit. Stir frequently to keep skin from forming.
step 13
Whip Heavy Cream (1/2 cup) and Vanilla Extract (1 tsp) in a cold bowl until the cream forms stiff peaks.
step 14
Add chocolate mixture into the whipped cream and gently fold until you have a smooth, cohesive mixture. Let it chill completely until thick and mousse like.
step 15
To form the cake, cut it into 2 or 3 layers. Poke holes all over the cake with a fork and brush with Simple Syrup (to taste) to keep it moist.
step 16
Add a dollop of the chocolate mousse in the center. Spread it leaving about an inch on all sides.
step 17
Add Cookies (1/4 cup) and Milk Chocolate Chips (1/4 cup) on top of the mousse.
step 18
Close with the next layer of the cake. Again poke holes, and brush with sugar syrup. And cover with the thick truffle frosting. Use a cake knife to smooth it out as much as possible.
step 19
Design the top as you please with the frosting and cookie!