First, preheat your oven at 180 degrees Celcius.

Now take a medium-sized bowl and put plain flour, cocoa powder, baking soda, and baking powder.

Use a spoon or spatula to mix this dry mixture together then sift the dry mixture into a different bowl and set aside.

Now for the wet mixture. In a food processor put yogurt, powdered sugar, vanilla essence, and butter (soften it before.)

With the help of your food processer mix all of your wet ingredients very well until you get a creamy mixture.

Now that it is creamy add your dry mixture into the food processor as well and mix everything very well. If you are using unsalted butter make sure you put salt.

Keep mixing this mixture until you get a uniform batter.

Before we bake it, add some walnuts into your batter and mix it inside.

Now, take out your medium-sized baking tray and pour your batter inside (go to the notes section to see tips on pouring batter)

Bake your brownies for 25 - 30 minutes (check notes to see how it is ready)

Enjoy your brownies!