Preheat oven to 350°F. Spray a 9-inch square baking dish with cooking spray. Set aside.
In a large bowl combine ¾ cup granulated sugar, flour, ¼ cup cocoa powder, baking powder, and salt. Stir in the milk, melted butter, and vanilla. Using hand mixer, beat mixture until smooth.
Pour the batter into the 9-inch baking dish.
In a small bowl, combine the remaining ½ cup granulated sugar, remaining cocoa powder, and the brown sugar. Sprinkle this mixture evenly over the batter.
Pour the hot water overtop. Do not stir!
Bake for 32-35 minutes or until center is almost set. Remove from the oven and let stand for 10 minutes.
Serve in individual dishes. Top with ice cream or fresh whipped topping.
Notes
Making this hot fudge cake recipe ahead of time is kind of hard because you want to eat it warm, after you remove it from the oven to get that self saucing chocolate pudding effect. Store any leftovers covered in the fridge for 1-3 days. The cake is much better fresh, but leftovers are still yummy! Warm them up a bit in the microwave before eating again. I don’t recommend freezing this cake due to the fudge sauce that forms on the bottom. Carefully pour the water over the chocolate/sugar mixture. You don’t want to pour with such force that you create a hole or dip in the sugar mixture or cake batter underneath. I like to pour the water slowly and move my hand around the pan so the water isn’t just pouring into one spot. For troubleshooting and FAQs, see my blog post. recipe source: adapted from Hersheys.com