Step 1: Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
Step 2: Peel and cube the sweet potato. Steam or boil until very soft (10-12 minutes). Drain well if boiled. Mash until smooth. You should have 1 to 1.5 cups of mashed sweet potato.
Step 3: In a large bowl, combine the mashed sweet potato, almond butter, maple syrup, and vanilla extract. Stir until smooth and well-combined.
Step 4: Sift in the unsweetened cocoa powder, then add the almond flour, baking powder, and salt to the wet mixture. Stir until just combined, being careful not to overmix. The batter will be thick.
Step 5: If using, gently fold in the dairy-free chocolate chips until evenly distributed.
Step 6: Pour the brownie batter into the prepared 8x8-inch baking pan. Spread evenly with a spatula.
Step 7: Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (not wet batter).
Step 8: Remove from the oven and let cool in the pan for 10-15 minutes. Then, use the parchment paper overhang to lift the brownies onto a wire rack to cool completely before slicing.
Step 9: Slice into squares and serve. Store leftovers in an airtight container at room temperature for 3-4 days or refrigerated for up to a week.