Preheat the oven to 180°C (160 fan/ Gas 4/ 350F) and line a 20cm (8'') square baking tin with baking paper.
Mix together the melted butter and sugars.
115 g Unsalted Butter, 150 g Light Brown Sugar, 50 g Caster Sugar
Beat in the egg, pumpkin puree, and vanilla extract.
1 Egg, 1 teaspoon Vanilla Extract, 100 g Pumpkin Puree
Fold in the dry ingredients (plain flour, salt, baking powder, cinnamon, ginger, nutmeg, and chocolate chips) until the blondie batter is smooth.
150 g Plain Flour, ½ teaspoon Salt, ½ teaspoon Baking Powder, 100 g Chocolate Chips, 1½ teaspoon Cinnamon, 1 teaspoon Ground Ginger, ⅛ teaspoon Nutmeg
Spoon the mixture into the prepared tin and bake for 20-25 minutes. Bake until the edges begin to pull away from sides of the tin and a skewer inserted into the centre comes out with just a few moist crumbs on it. Cool completely before cutting into bars!