Preheat Oven: Set the oven to 350°F. Line a baking sheet with a silicone mat or parchment paper and set it aside.

Cream Butter and Sugar: In a mixing bowl, use a hand mixer to blend the butter and sugar until they are well combined.

Add Wet Ingredients: Mix in the eggs and vanilla extract until fully incorporated.

Combine Dry Ingredients: Sift together the flour, cocoa powder, baking soda, and salt. Gradually add this mixture to the wet ingredients, stirring until well mixed.

Mix in Add-ins: Stir in 1 cup of mini milk chocolate chips and 1 cup of chopped toasted hazelnuts.

Shape Dough: Scoop out heaping tablespoon-sized portions of dough, roll them into balls, and place them on the prepared baking sheet.

Flatten and Top: Gently flatten each dough ball with your palm to about half an inch thick. Top with a few additional milk chocolate chips and chopped hazelnuts.

Bake: Continue shaping and topping the cookies, leaving two inches of space between them on the sheet. Bake for 12 minutes.

Cool: 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.