Eggless chocolate brownie

Ingredients 

All purpose flour(maida) :3/4 cup
Powdered sugar : 1cup
Salt : 1/4tsp
Baking powder : 2tsp
Cocoa powder :1/3 cup
Unsalted butter :10 g
Walnut :1/2 cup (optional)
Vanilla  essence :1 1/2tsp

Method
:Preheat the oven to 180degree C  for at least 10mins
:First melt the butter in stove and let it cool
:Take all purpose flour,salt, sugar and baking powder in a bowl
:Now sift the coco powder,because of that there will be no lumps of coco powder
:Mix we'll till incorporated well
:Now put  the melted and cooled butter in to the mix
:Add vanilla extract
:whisk we'll till everything gets mixed
:Add dry flour mixture
:Mix we'll
:Add walnuts  if using and mix well
:Now pour the batter in to the pan
:  Spread butter over the tray,so it will be easy to lift up after it bakes
:Bake it in to preheated oven  for 30 mins
:check by inserting a toothpick in the center,if it comes out clean then it is ready
:After it cools,using a sharp knife cut it in to pieces as per your desire