For the Cake:

1. Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper.
2. In a large mixing bowl, sift together the flour, baking powder, baking soda, salt, cocoa powder, granulated sugar, and brown sugar.
3. In another bowl, whisk the eggs, milk, vegetable oil, and vanilla extract until well combined.
4. Gradually add the wet ingredients to the dry ingredients, mixing until smooth.
5. Stir in the 1 cup of chocolate chips.
6. Carefully add the boiling water to the batter, mixing gently. The batter will be thin, but this is normal.
7. Divide the batter evenly between the two prepared cake pans.
8. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Let the cakes cool in the pans for 10 minutes before transferring to a wire rack to cool completely.

For the Ganache:

1. In a small saucepan, heat the heavy cream over medium heat until it begins to simmer (do not boil).
2. Remove from heat and stir in the chocolate chips, allowing them to melt completely. Stir in the butter (if using) for added shine and smoothness.
3. Let the ganache cool slightly before using.

To Assemble:

1. Place one cake layer on a serving plate or cake stand.
2. Spread a layer of the chocolate ganache over the top of the first cake layer.
3. Place the second cake layer on top and pour the remaining ganache over the entire cake, spreading it evenly.
4. Sprinkle the 1/2 cup of chocolate chips on top of the ganache for extra chocolatey goodness.

To Serve:

1. Let the cake set for a few minutes to allow the ganache to firm up.
2. Slice and serve this rich, decadent cake to your guests or enjoy a slice all to yourself!