1. Preheat the oven to gas mark 4/ 350 degrees F. Grease a baking dish with butter and line with a parchment paper.
2. In a bowl, cream together sugar, orange zest and unsalted butter.
3. Add in the egg, vanilla essence, ground almonds, fresh orange juice and flour. Mix well.
4. Drop the batter into the prepared baking sheet. Bake in the oven for 20 minutes.
5. Take out the cookies and place on a cooling rack to cool for a few minutes.
6. Meanwhile in a bowl, add in the chocolate bars and melt in microwave.
7. Stir in the orange essence and mix well.
8. Dip half of cookies into the chocolate mixture and set aside to get cool.