Start by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent the cookies from sticking.

In a medium bowl, whisk together the flour, baking soda, salt, and cocoa powder. Make sure the dry ingredients are well combined, as this will ensure even mixing later.

In a separate, large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar. You can do this by hand, but I recommend using an electric mixer for a smoother, fluffier texture. Mix on medium speed for about 2-3 minutes until the mixture is light and creamy.

Add the egg and vanilla extract to the butter-sugar mixture. Beat until the mixture is smooth and fully incorporated.

Gradually add the dry flour mixture to the wet ingredients, mixing until just combined. You don’t want to overmix at this stage, as that can lead to dense cookies.

Once the dough has come together, gently fold in the chocolate chips and chopped hazelnuts. Be sure to distribute them evenly throughout the dough for that perfect bite of chocolate and hazelnut in every cookie.

Use a spoon or cookie scoop to form tablespoon-sized portions of dough. Roll them into balls and place them onto your prepared baking sheet. Make sure there is enough space between each cookie to allow for spreading during baking (about 2 inches apart). If you’d like, sprinkle a pinch of sea salt on top of each cookie for a gourmet touch.

Bake in the preheated oven for 12-15 minutes, or until the edges are golden brown and the centers are set. Don’t worry if they’re still a bit soft in the middle—they’ll firm up as they cool. If you prefer a chewier cookie, take them out closer to 12 minutes.

Once baked, transfer the cookies to a cooling rack and let them cool for 5-10 minutes before devouring. If you can resist, they’ll hold up better if left to cool completely, but I always find it hard to wait!