Combine 2 cups milk and sugar in a heavy bottomed sauce pan and bring to a boil.

In the meantime, whisk custard powder and cocoa in the remaining 3tbsp milk, making sure that there are no lumps.

Once the milk comes to a boil, remove from heat and slowly add the custard powder mixture whisking continuously.

Bring the mixture to a simmer whisking continuously until the mixture thickens, about 2-3 minutes. Remove from heat and mix vanilla extract. Let the mixture cool completely.

Add topping of Brownie chunks with chocolate sryup. Served then.