Preheat the oven to 180 C / Gas 4. Combine flour, baking powder, bicarbonate of soda, cinnamon, nutmeg, ground cloves and salt; set aside.
In the second bowl, cream together the 125g of butter and caster sugar. Add pumpkin puree, egg and 1 teaspoon of vanilla to butter mixture, and beat until creamy. Mix in dry ingredients. Drop on baking tray by tablespoonfuls; flatten slightly.
Bake for 15 to 20 minutes in the preheated oven. Cool cookies, then drizzle icing with fork.
To make icing: Combine icing sugar, milk, 1 tablespoon melted butter and 1 teaspoon vanilla. Add milk as needed, to achieve drizzling consistency.