Preheat your oven to 325°F (163°C) and spray a 9×13 inch metal baking dish with nonstick cooking spray.

In a medium microwave-safe bowl, add the milk chocolate chips and microwave in 30-second intervals, stirring in between until melted and smooth. Set aside to cool slightly.

In a medium bowl, whisk together the flour, cocoa powder, salt, and baking soda.

In a stand mixer, add the eggs and granulated sugar. Mix at medium speed until light and fluffy, about 5 minutes.

With the mixer on low, add the melted chocolate, vegetable oil, water, and whiskey. Mix until smooth.

Gradually add the dry ingredients to the wet mixture, mixing gently until no lumps remain.

Pour the batter into the prepared pan and bake for 46-48 minutes or until a toothpick inserted comes out with a few crumbs.

While the cake cools, prepare the ganache by heating the semi-sweet chocolate chips, heavy cream, and the remaining whiskey in a saucepan over low heat. Stir until melted and smooth.

Allow the ganache to cool for about 5 minutes before pouring it over the cooled cake. Let it set slightly before cutting.