Pre-heat your oven to 180C and line a 9 inch rectangle baking tin with grease proof paper.
Place a couple of inches of water into a sauce pan and bring to the boil. Turn off the heat and place a bowl over the hot water.
Break the chocolate into cubes and add to the bowl, melt gently with the butter (also cut into cubes), stirring frequently.
Once the butter and chocolate have melted together, slowly stir in the sugar. You will be left with a glossy chocolate mixture.
Pour this into a large mixing bowl and beat in the pumpkin purée until smooth.
Leave the pumpkin and chocolate mixture for a few moments until cool and beat in the eggs.
Sift the flour, vanilla and spices into the batter mixture and fold gently until combined.
Finally, stir through the white chocolate chips
Pour the blondie mix into the lined tin.
Bake in the centre of the oven for 25 minutes or until the brownie mixture is set and a crisp top has formed with distinctive cracks.
Allow the blondies to cool in the tin before, cut into squares then carefully remove from the tin, peeling away the grease proof paper.