In a large mixing bowl, beat together 1 cup of softened, unsalted butter and 1 cup of Nutella using an electric mixer on medium speed until creamy and well combined, about 3-4 minutes.

Mix in 1/2 cup of brown sugar, 1/2 cup of granulated sugar, 1 teaspoon of vanilla extract, and a pinch of kosher salt until smooth and fluffy.

Crack in one large egg and one egg yolk into the mixture, then blend on low speed until just incorporated.

In a separate bowl, whisk together 2 cups of all-purpose flour and 1 teaspoon of baking soda.

Gradually add this dry mixture into the wet batter, mixing gently until just combined.

Next, add in 1 cup of chopped hazelnuts and fold them into the dough using a spatula.

Gently fold in 1 cup of semi-sweet chocolate chips.

Wrap the cookie dough tightly in plastic wrap and refrigerate for at least 1 hour.

Scoop out tablespoon-sized portions of dough and roll them into balls, then roll each ball in finely chopped hazelnuts.

Place the coated cookie dough balls onto the prepared baking sheet, spacing them about 2 inches apart.

Bake in the preheated oven for 11-12 minutes or until the edges are just golden and the centers look set but still soft.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack.

Drizzle some melted Nutella over the warm cookies before they cool completely.