Set your oven to 350°F right away.
This ensures even baking from the start.
Let it warm up while you prepare everything.
Combine flour, cocoa, sugar, and salt together.
Whisk them until everything blends well and smooth.
Add eggs, melted butter, and vanilla extract next.
Stir until you get a thick batter.
Don't overmix or it becomes tough instead.
Pour the brownie batter into your baking dish.
Spread it evenly using a spatula or spoon.
Make sure it reaches all the corners nicely.
Mix brown sugar and cocoa powder in a bowl.
Sprinkle this mixture over the brownie batter evenly.
Pour hot water gently over the entire surface.
Don't stir it at all right now.
Place the dish in your preheated oven immediately.
Bake for about 40-45 minutes until set.
The top should look like a cake layer.
The pudding forms magically underneath while it bakes.
Let it cool for 15 minutes before serving.
The pudding thickens as it sits and cools.
Serve warm with ice cream on top optionally.