Preheat oven to 350 degrees F. Liberally grease an 8" or 9" square baking pan with cooking spray. Set aside.

Whisk together the flour, 1/2 cup of the granulated sugar, 1/4 cup of the cocoa powder, baking powder, and salt in a bowl until combined. Add in the milk, oil, and vanilla, stirring until just combined.

Scrape the batter into the prepared pan and smooth out the top. Batter will be very thick. Meanwhile, combine the remaining 1/4 cup granulated sugar, 1/4 cup cocoa powder and the brown sugar together in a small bowl until combined. Sprinkle this mixture liberally over the cake batter, covering it completely. It seems like a lot, but use it all! Then generously pour the hot strong black coffee over the top.

Carefully bake for 23-28 minutes or until the top appears set and the edges are bubbly. Cool for about 10 minutes before cutting into slices to serve, making sure you spoon the sauce (on the bottom) over the top!