Preheat the oven to 350 degrees F.

Butter and flour three 8-inch round cake pans and line bottoms with parchment.

Cream together the butter and sugar. Add in the eggs, 1 at a time, mixing well after each.

Whisk together the cocoa powder and hot water.

Whisk together the flour, baking soda, baking powder and salt.

Add 1/3 of the dry mixture into the creamed butter/sugar mixture. Mix. Add in 1/2 of the warm cocoa/water mixture. Mix again. Repeat till all the flour and cocoa are combined.

Divide batter evenly among the cake pans. Bake for 40 to 50 minutes till a toothpick inserted comes out clean.

For the buttercream: Cream together the butter, shortening, and peanut butter. Gradually add in the powdered sugar. Add in the milk and vanilla. Mix till combined.

To assemble: Roughly chop 1 box of Tagalong cookies. Starting with the first layer of cake, spread about 1/4 cup of frosting across the top. Sprinkle 1/3 of the chopped cookies in the middle of the layer, leaving a 1/2 inch border around the edge. Top with the next layer of cake and repeat this process 1 more time, then top with last layer of cake. Cover the whole cake with the peanut butter frosting. Chill for at least 2 hours.

After the cake has chilled, make the ganache. Heat the heavy cream to just before boiling point.

Pour over the chocolate chips. Let sit for a couple of minutes and whisk smooth. Let cool slightly. Pour warm ganache over the top of the chilled cake and let drip down the sides. Use a spoon to help it flow over the edge. Top the cake with more chopped tagalongs in the center.