Preheat the Oven: Begin by preheating your oven to 180°C (350°F). Line a muffin tin with your cupcake cases.
Mix Wet Ingredients: In a large bowl, combine the sunflower oil, eggs, and buttermilk. Whisk until the mixture is well-blended.
Combine Dry Ingredients: In another bowl, mix together the brown sugar, ground hazelnuts, flour, baking cocoa, baking powder, and baking soda until evenly distributed.
Blend Together: Gradually add the dry ingredients to your liquid mixture, stirring until just combined. Be careful not to overmix; a few lumps are okay!
Fill Muffin Cases: Spoon the batter evenly into the muffin cases, filling them about two-thirds full.
Bake: Place the muffin tin in the oven and bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean.
Cool: Allow the cupcakes to cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely.
