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.
Step 2: In a large mixing bowl, whisk together the melted butter and brown sugar until smooth and well combined.
Step 3: Add the blotted pumpkin puree, egg, and vanilla extract. Whisk vigorously until the mixture is homogeneous and slightly lightened in color.
Step 4: In a separate bowl, sift together the flour, cinnamon, ginger, nutmeg, cloves, baking soda, and salt.
Step 5: Gradually fold the dry ingredients into the wet ingredients using a spatula. Mix until just combined, being careful not to overwork the batter.
Step 6: Gently fold in 3/4 cup of the white chocolate chips.
Step 7: Spread the batter evenly into the prepared pan and sprinkle the remaining 1/4 cup of white chocolate chips on top.
Step 8: Bake for 25-30 minutes, or until the edges are golden and a toothpick inserted into the center comes out with a few moist crumbs.
Step 9: Allow the spiced pumpkin blondies with white chocolate to cool completely in the pan before slicing into 16 squares.