Pre-heat the oven to 150°C (300°F) and line a baking tray with grease-proof paper.
Cream butter and sugar, then beat in the milk and syrup.
Mix the baking soda, oats and flour together and then add to the wet ingredients, stirring well to combine.
Take roughly one tablespoon of dough and form into a ball, then place on the baking tray. Using the palm of your hand, flatten into a rough round shape and do the same with the rest of the dough (they will be a very rustic circle, so don't worry too much about getting it too neat). Leave space in between as they do spread when baking.
Bake for around 15 until they are golden (they will feel very soft, but that's fine). Take care not to overcook them as they burn easily - err on the side of caution and remove them a little earlier rather than later. Remember that if you make smaller cookies, they will need less time, so keep an eye on them.
Because they are so soft, let them sit on the tray for around ten minutes and then transfer them to a wire rack to cool completely.
For the topping: melt the chocolate and syrup in a Bain Marie, stirring frequently as it melts. Finally, quickly beat in the butter. Spread over the cooled cookies. Enjoy!