- Preheat oven to 180°C/165°C fan forced. Lightly grease a 23cm x 23cm x 2cm baking pan and line with baking paper.
- Whisk flour, baking powder and salt in a large bowl. Combine half the chocolate and butter in a large stainless-steel bowl. Set bowl over a saucepan of simmering water.
- Remove bowl from heat; whisk in sugar, cocoa powder, egg, vanilla, and yoghurt. Fold wet ingredients into dry ingredients. Fold in remaining chocolate chips. Pour mixture into prepared pan.
- Bake until a skewer inserted into centre of slice comes out with a few moist crumbs attached, 25-30 minutes. Let slice cool completely before cutting into squares with a sharp knife.
- Note: Add 1 cup chopped walnuts for extra flavour and texture.
Click here for the original recipe by Jalna.