Place 2 cups of the toasted hazelnuts in a food processor and process until finely chopped. Add the oil and process until the nuts essentially liquify and a paste/butter forms, scraping the bowl as needed. Set aside. Finely chop the 1/2 cup of nuts and set aside.

In a medium-sized bowl whisk the bread flour, baking soda, baking powder, and salt. Add the chocolate chips and chopped nuts, and whisk again. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, combine the two sugars and the melted butter on medium-high speed. Beat until the mixture lightens and thickens, about 3 to 5 minutes. Add the hazelnut butter and mix until combined. Add the yolks, egg, and vanilla and mix again until fully incorporated.

Add the dry ingredients and mix on low speed briefly, and stop the mixer when streaks of flour still remain. Remove the bowl from the mixer and finish mixing the dough by hand with a rubber spatula. Line a baking sheet with parchment paper. Scoop the dough using a 1/4 cup ice cream scoop, place the scoops on the sheet and refrigerate for at least 24 hours and up to 72 hours.

When ready to bake the cookies, preheat the oven to 375 degrees and transfer as many cookies as you would like to bake to a new parchment-lined pan. Sprinkle with Maldon sea salt and bake the cookies for 12 minutes, rotating after 6, until the cookies are beginning to brown. Let them cool on a rack, but serve while still warm, if possible.