This hot fudge pudding cake is a self-saucing chocolate dessert with soft cake on top and rich fudge sauce underneath, easy, from scratch, and best served warm.
Preheat the oven to 350°F / 180°C ( 320°F convection / 160°C fan). Lightly grease an 8-inch (20 cm) square baking dish.
In a medium bowl, whisk together 125 g all-purpose flour, 150 g granulated sugar, 3 tbsp unsweetened cocoa powder, 2 tsp baking powder, and ¼ tsp salt.
Add 120 ml whole milk, 45 g unsalted butter, melted, and 1 tsp vanilla extract. Stir just until combined, then spread the batter evenly in the prepared baking dish.
In a small bowl, mix 100 g granulated sugar, 100 g packed brown sugar, and 25 g unsweetened cocoa powder . Sprinkle the mixture evenly over the batter. Do not stir.
Carefully pour 300 ml hot water evenly over the top. Do not mix; the batter will look very thin, and that’s exactly how it should be.
Bake for 25–30 minutes, until the top looks set and slightly cracked, but the center still appears soft. Let it rest for 10 minutes before serving. Spoon into bowls, making sure to scoop all the way down to get the warm fudge sauce underneath.
Notes
Do Not Stir After Adding Water: Once you pour the hot water over the top, resist the urge to mix. The layering is what creates the cake on top and the fudge sauce underneath.Remove It at the Right Time: I take it out when the top looks set and slightly cracked, but the center still feels a little soft. That soft center is what keeps the sauce generous and rich.Use Properly Hot Water: I like to use freshly boiled water. If the water isn’t hot enough, the sauce layer may not develop as deeply or smoothly.Let It Rest Before Serving: Giving it 10 minutes to sit helps the sauce thicken slightly, so you get that perfect spoonful with both cake and fudge together.