Preheat the oven to 350F (180C) and grease the bottom of one 9x13-inch pan.
In a large bowl mix the flour, baking powder and cocoa powder. In a large measuring cup mix the milk and heavy cream, brandi and vanilla extract.
Beat the butter and sugar on medium speed for 3-4 minutes, until light and fluffy. Scrape the sides and bottom of the bowl.
Increase the speed to medium-high and add the eggs one at a time, waiting for each egg to fully incorporate before adding the next. Scrape the side and bottom of the bowl.
Reduce the speed to low, then add the flour mixture in three additions alternating with the wet ingredients, starting and ending with the flour mixture.
Once you added the last portion of the flour, use a rubber spatula to fully incorporate the cake batter.
Pour the cake batter into the prepared pan and bake for 28-30 minutes, until a toothpick comes out from the center of the cake with a few moist crumbs.
Remove from the oven and allow to cool while you make the ganache.