Created by ImPat on February 9, 2018
Step 1: Position a rack in the centre of oven and preheat oven to 180C/160C fan forced.
Step 2: Spray a 20cm square baking pan with non-stick cooking spray and line the base and 2 opposite sides with baking paper allowing the sides to overhang.
Step 3: Place 170 grams of the chocolate and the butter in a medium heatproof bowl over a saucepan of simmering water and stir until melted and smooth and sit aside for 10 minutes to cool, or until lukewarm.
Step 4: In a bowl, whisk the sugar, eggs, vanilla and salt to blend and then whisk in the chocolate mixture and stir in flour and then 1 cup (120 grams) pecans.
Step 5: Transfer to the prepared pan and bake for 40 minutes or until edges are set and centre if still slightly wobbly and transfer to a wire rack and set aside to cool completely.
Step 6: Meanwhile, place sweet potatoes in a saucepan and add enough water to cover by 2.5cm and bring to a simmer over medium heat and cook for 20 minutes or until potatoes are tender and drain the sweet potatoes, transfer to blender and blend until smooth.
Step 7: Add the remaining chocolate and blend until smooth and transfer to a bowl and set aside, stirring occasionally, for 1 hour or until the frosting has cooled to room temperature and can hold soft peaks.
Step 8: Lift brownie from pan and spread frosting over brownies and top with the remaining pecans.
Step 9: Cut into 16 squares. wiping knife with a hot moist cloth after each cut.