Preheat oven to 180C/350F for 10 mins.

Line an 7X7 inch baking dish with parchment paper or aluminium foil, and brush all sides with butter.

Sift flour, salt, baking powder and cocoa powder.Whisk well and set aside

In a double boiler set over low heat, melt butter and chocolate. Let it cool

Combine sugar and yogurt. Add the cooled chocolate mixture.

Add the flour mixture to the liquid mixture and mix till just combined. Do not overmix. The mixture will be on the thicker side. If u wish u can add chopped walnuts/ chocolate chips now.

Pour into the prepared baking pan and bake for 35 - 40 minutes at 180°C.Start checking if the brownies are cooked by inserting a fork or toothpick in the center at the 35 minute mark.

Once baked, cool the brownies in the pan completely before inverting them onto a metal rack. Cut into slices and serve.