*Roast the whole peeled hazelnuts on a cookie sheet in a pre-heated 350F (180C) oven for about 5-6 minutes. Immediately move to a clean bowl.
Pre-heat oven to 350F (180C). Line two cookie sheets with parchment paper.
Roast the whole hazelnuts (1/3 cup + 1 tablespoon and the 20 whole hazelnuts) for about 5-6 minutes. Move them to a clean bowl, remove 20 hazelnuts and set aside. The remaining hazelnuts place in a food processor and pulse until finely chopped (see photo). Set aside.
In the bowl of the mixer cream the butter and sugar until fluffy about 2-3 minutes.
Add the flour, chopped nuts, egg yolk, milk and vanilla. Mix just until combined into a dough.
Either place the dough in a pastry bag with a large star tip or drop by heaping teaspoonfuls (or half and half) on the prepared cookie sheets. Place a roasted whole hazelnut on each cookie round and bake for approximately 15-20 minutes or until golden. Let cool 10-15 minutes on the cookie sheet then move to a wire rack to cool completely. Enjoy!