Prick some holes in the skin of the butternut squash, and then place in the microwave. Set the microwave on high and cook the pumpkin for about 20 minutes until soft and tender. Allow to cool completely. Halve the butternut squash lengthwise and remove the seeds with a spoon. Weigh out 400 grams of flesh and purée with the hand blender until smooth. Set the rest of the butternut squash aside.
Preheat the oven to 180 °C. Place a muffin case in each cavity of the muffin tin.
Reserve 12 attractive walnut halves to use as a garnish. Roughly chop the rest.
Beat the butter with the brown sugar using the mixer for about 5 minutes until light and airy. Add the eggs one at a time. Only add the next egg when the previous egg is fully incorporated.
Sieve the flour, gingerbread spices and a pinch of salt onto the creamed butter. Use a spatula to gently fold the dry ingredients into the butter. Fold the chopped walnuts through the batter. Divide it evenly over the muffin cases.
Bake in the middle of the oven for about 20 minutes until cooked and golden brown. Leave the muffins to cool in the tin for 5 minutes. Then remove the muffins in the cases and let them cool completely on a wire rack.
Melt the white and dark chocolate separately au bain-marie. Dip the muffins into the melted white chocolate and leave to harden a little.
Put the dark chocolate in a small piping bag or baking paper cone. Pipe a spiral onto the white chocolate topping on each muffin. Run the cocktail stick from the centre to the edge of the muffin to create a cobweb effect. Use a melon baller to scoop small balls from the butternut squash. Arrange them on the muffins. Attach the walnuts using a little melted chocolate.
