Preheat oven to 180 degrees C. Melt the butter and mix in with the crushed ginger nuts. Line the bottom of a spring form tin or pie tin with this mixture and press it down firmly. Bake in the preheated oven for 10 minutes.
Beat cream cheese until smooth. Mix in the pumpkin, brown sugar, flour, vanilla and spices. Mix in the milk and eggs. Beat until well combined then pour onto the cooled base and refrigerate until firm.