Preheat the oven to 350 F (180 C). Line an 8 × 8 inch (2 L) pan with parchment paper so that you have some overhanging the sides, then lightly coat with baking spray. Set aside.

Place the sweet potatoes in the microwave and cook on high for 7 to 10 minutes or until completely softened. Once cool enough to handle, scoop out 2 cups (500 mL) of the flesh and discard the skin. Place in a larger mixing bowl, then beat until mashed and fairly smooth. Beat in the melted coconut oil or butter until combined, then beat in the maple syrup and vanilla extract. Beat in the eggs one at a time, stopping to scrape down the bowl as needed.

In a separate bowl, stir together the flour, cocoa powder, cinnamon, nutmeg, baking powder, and salt. Add the dry ingredients to the wet ingredients and mix gently, just until the dry ingredients are incorporated. Fold in the chocolate chips.

Scrape the batter into the prepared baking pan and smooth the top. Bake for 25-30 minutes, just until a toothpick inserted in the center comes out clean. Place the pan on a wire rack and let cool completely. (The brownies taste better the longer they sit). Gently lift the brownies out of the pan onto a wire rack. Slice and serve.

Store leftover brownies in an airtight container in the refrigerator for up to four days or freeze for 2 months.