Preheat the Oven: Preheat the oven to 180°C (350°F) and line a baking sheet with parchment paper.
Toast the Hazelnuts: Spread the 150 grams (1 cup) raw hazelnuts on the prepared baking sheet and roast for about 8 minutes, until fragrant.
Cool and Grind the Hazelnuts: Let the roasted hazelnuts cool slightly, then process them in a food processor until they become a hazelnut meal. Keep the oven on and set the same baking sheet aside for baking the cookies. Combine the Wet Ingredients: In a large mixing bowl, whisk together the 80 grams (⅓ cup) softened coconut oil, 2 tablespoons water or non-dairy milk, and 2 teaspoons vanilla extract. The mixture will not fully combine at this stage, which is normal. Add the Coconut Sugar: Whisk the 150 grams (¾ cup) coconut sugar into the mixture until incorporated and a thick paste forms.
Build the Dough: Add the ground hazelnut meal, 100 grams (1 cup) rolled oats, 150 grams (1 cup) light spelt flour, ½ teaspoon baking soda, and ¼ teaspoon sea salt. Stir with a wooden spoon or spatula just until combined; a few streaks of flour are fine. Fold in the Chocolate: Add the 100 grams (½ cup) chopped dark chocolate or chocolate chips and fold gently until evenly distributed throughout the dough.
Portion the Cookies: Using a spoon or cookie scoop, portion the dough into 16 even scoops on the prepared baking sheet.
Flatten the Dough: Gently flatten each portion slightly with the palm of your hand.
Bake the Cookies: Bake at 180°C (350°F) for 8–10 minutes, or until the cookies are lightly golden in colour.
Cool on the Baking Sheet: Leave the cookies on the baking sheet for 10 minutes after baking so they can cool and set.
Finish Cooling: Transfer the cookies to a wire rack and allow them to cool completely.
Store the Cookies: Keep the cooled cookies in a sealed container for up to 5 days, or freeze them for up to 3 months.