Preheat the oven to 180C/350F/Gas 4. Line two baking trays with non-stick parchment. Melt the butter and the golden syrup in a pan over a low heat. Set aside to cool slightly.
Combine the sugar, flour, baking powder, salt and spices and mix well to combine. Stir in the rolled oats and mix thoroughly. Pour in the melted butter and syrup and stir until well combined. Then stir in the beaten eggs and the stem ginger.
Spoon in even, heaped teaspoons onto the lined baking trays, leaving room for them to spread. Bake in the oven for 8-10 minutes. Remove the biscuits from the oven and set aside to cool completely.
Melt the chocolate in a bowl suspended over a pan of barely simmering water (do not let the bottom of the bowl touch the water). Dip the biscuits in the melted chocolate and place on a cooling rack until the chocolate has set.