01 -
Turn your oven on and set it to 350°F (175°C).
02 -
Use a 9×13 dish to melt the butter right in your oven. As soon as it's fully melted, take it out and keep it nearby.
03 -
In a mixing bowl, toss together the sugar, cocoa powder, salt, flour, baking powder, vanilla, and milk until smooth. Gently spoon this batter over the melted butter sitting in your dish, but don't mix them up.
04 -
Stir the cocoa powder and sugar for the topping in a separate bowl. Sprinkle it over the batter in your dish. Carefully pour the boiling water on top, and leave it alone—no stirring!
05 -
Bake in your hot oven for 35-40 minutes until the top looks set. The bottom part should still be kind of liquidy and gooey—that's the way it's supposed to be!
06 -
Give it about 15 minutes to cool slightly. Serve warm with some ice cream, if you'd like!