Preheat your oven to 350 degrees F. Line a baking sheet with parchment paper or a silicone mat.
In a large mixing bowl, beat together the butter and sugars until fluffy, about 1 minute. Add vanilla and one egg, mix until combined. Add the second egg and mix until combined. Scrape the sides of the bowl as needed.
In a medium mixing bowl, stir together the flour, salt, and baking soda. Add the dry ingredients to the wet ingredients and mix until just combined.
Use a wooden spoon to stir in the dark chocolate chips and hazelnuts by hand. Use a small cookie scoop (or 1 tablespoon measuring spoon) to portion the dough onto your prepared baking sheet.
Bake for 10 minutes, or until the cookies are set and the bottom edges are golden brown. Carefully remove from the oven. Allow to cool on the pan for 2 minutes before transferring to a wire rack to cool completely.