In medium bowl, place sweet potato puree, sugar, oil, egg and vanilla extract. Mix until well combined.
Add flour and cocoa powder. Mix until well combined. Fold in 2/3 of chopped chocolate.
Pour batter into Silicone Rectangular Form and smooth top to form even layer. Sprinkle remaining chocolate pieces over the top.
Place in microwave and cook on 80% power for 5-6 minutes or until toothpick inserted in center comes out clean.
Let cool slightly, cut into squares using spatula and serve.