1. Preheat your oven to 175°C (350°F). Line a baking sheet with parchment paper.

2. In a large mixing bowl, cream together 115g of butter, 100g of brown sugar, and 100g of granulated sugar until smooth and well combined. Beat in 1 egg until the mixture is silky and even.

3. In a separate bowl, whisk together 285g of flour, 100g of oats, 1 teaspoon of cinnamon, 1 teaspoon of baking soda, and 1/2 teaspoon of salt. Add 60g of chopped hazelnuts and 60g of currants to the dry ingredients and stir until they are evenly distributed.

4. Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms. Be careful not to overmix.

5. Scoop tablespoon-sized balls of dough onto the prepared baking sheet, leaving about 5cm (2 inches) of space between each cookie to allow for even spreading.

6. Bake for 12-15 minutes, or until the edges are lightly golden. Remove the cookies from the oven and let them cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

7. If desired, melt some chocolate and drizzle it over the cooled cookies. Let the chocolate set before serving.