Step 1: Preheat your oven to 350°F (175°C) and grease an 8x8 inch square baking pan or line it with parchment paper for easy removal of your roasted butternut squash and maple blondies.
Step 2: In a medium saucepan, melt the butter over medium heat, whisking constantly until it turns a deep golden brown and smells nutty. Remove from heat immediately and let it cool.
Step 3: In a large mixing bowl, whisk together the browned butter, brown sugar, and pure maple syrup until well combined.
Step 4: Add the roasted butternut squash puree, egg, and vanilla extract to the butter mixture. Whisk until the batter for the roasted butternut squash and maple blondies is smooth.
Step 5: Sift in the flour, cinnamon, ginger, nutmeg, salt, and baking powder. Gently fold the dry ingredients into the wet ingredients using a spatula until just combined.
Step 6: Spread the batter evenly into the prepared pan and bake for 22-27 minutes, or until the edges are golden and a toothpick inserted into the center comes out with just a few moist crumbs.
Step 7: Allow the roasted butternut squash and maple blondies to cool completely in the pan before slicing into squares.