01 -  Preheat oven to 350°F. Line an 8x8-inch baking pan with parchment paper or lightly coat with oil. 
 02 -  In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger until evenly distributed. 
 03 -  In a large bowl, whisk canned pumpkin, pure maple syrup, brown sugar, oil, eggs, and vanilla extract until mixture is smooth and uniform. 
 04 -  Gently fold the dry ingredient mixture into the wet mixture using a spatula. Stop mixing once ingredients are fully incorporated without overmixing. 
 05 -  Pour batter into prepared pan and smooth the surface. Sprinkle chopped nuts evenly over the top, if using. 
 06 -  Bake at 350°F for 28 to 32 minutes, until a toothpick inserted in the center comes out clean or with a few moist crumbs. 
 07 -  Remove pan from oven and let bars cool completely on a wire rack before slicing. 
 08 -  Drizzle with additional maple syrup, if desired, just before serving.