Put all the skinned hazelnuts into a food processor and pulse. Add 1/3 cup neutral oil i.e canola, grapeseed or sunflower. Add a pinch of salt.
I store my hazelnut butter in an reusable peanut butter jar. The hazelnut butter smells heavenly like a potent Nutella and very creamy. These are good for a few months because the oil will preserve it. I doubt anyone can resist eating all of it in 2 weeks. The cost of making your own hazelnut butter may not be very much cheaper than buying it from the store but I get a satisfaction from knowing that I can make something so yummy so effortlessly in my own kitchen and with so little fuss. On top of that, I enjoy knowing what's in my food. Next time I will add some cocoa powder to make my own Nutella :)
I am planning to make a batch of these as Christmas presents for my friends. This will make better gifts than the usual Christmas cookies.