To make the gingerbread:Preheat the oven to 180C.
Butter a large,shallow baking tray,such as a lamington tin (30cm x 25cm x 3cm) and line the base with baking paper.
Whisk the egg and sugar until thick and creamy. Mix the golden syrup and milk together and stir into the egg mixture,along with the melted butter.
Sift together the flour,bi-carbonate of soda and spices and fold into the mixture. Spread on to the tray and bake for 40 minutes,or until a skewer inserted comes out clean. Turn out on to a wire rack and cool.
For chocolate topping:Break the chocolate into small pieces and place in a heatproof bowl. Stir over a pan of gently simmering water,until melted and glossy.
To serve: Scoop some vanilla ice-cream into a dish or glass,crumble over a generous amount of gingerbread,top with more ice-cream and more crumbled gingerbread,then drizzle with chocolate.