1 pkg. (15.25 oz) chocolate cake mix
1 package (3.4 oz) chocolate instant pudding and pie filling mix
1 cup whole milk
1/2 cup sour cream
4 large eggs
1 tsp. vanilla extract
2 cups semi-sweet chocolate chips
1 cup chopped walnuts (optional)
3 oz. unsweetened chocolate
4 1/2 Tablespoons butter
2 1/4 c. powdered sugar
3 to 6 Tablespoons milk (add slowly (a Tablespoon at a time) until desired consistency is reached)
1 1/2 tsp. vanilla extract
mini semi-sweet chocolate chips for garnish, optional
Grease and lightly flour a 12 cup bundt cake pan.
Preheat the oven to 350 degrees Fahrenheit. In the bowl of an electric mixer, mix together chocolate cake mix, chocolate instant pudding and pie filling, milk, sour cream, eggs, and vanilla. Scrape down the sides with a spatula throughout the process. Stir in 2 c. semi-sweet chocolate chips and chopped walnuts (nuts are optional).
Spread batter evenly around the prepared bundt cake pan. Bake for approximately 37-38 minutes, or just until a toothpick inserted into the center comes out clean. Cool in the pan on a wire rack for 20 minutes. Then run a butter knife carefully around the edges of the pan to help release it. Carefully invert the cake onto the wire rack and allow it to cool completely.
To make the ganache, melt unsweetened chocolate and butter in a medium saucepan over the stovetop on low heat, stirring constantly. Remove from heat. Stir in powdered sugar, alternately, with milk (a Tablespoon at a time), until a nice consistency is reached. Stir in vanilla extract. Pour ganache over the cake. Sprinkle with mini chocolate chips, if desired.