Step 1

If you're starting with hazelnuts that have skin, preheat the oven to 300ºF. (You can skip this step if starting with blanched nuts.) Spread the hazelnuts out into a single layer on a rimmed baking sheet, and place them in the oven to roast for 10 to 15 minutes, until the skins start to crack.

Step 2

When the hazelnuts are done roasting, let them cool until you can safely handle them. Transfer the hazelnuts to a dry towel, and rub them gently until the skins start to fall off. It's okay if you don't get the skin off every single nut; you're just trying to remove as much as possible. (The hazelnut skin is bitter, so the more you remove, the better the flavor will be.)

Step 3

Transfer the skinned hazelnuts to the bowl of a large food processor fitted with an "S" blade. Secure the lid and process the nuts for about 5 minutes, stopping to scrape down the sides of the machine as you go. I usually scrape the sides every minute or so, if the ground hazelnuts keep crawling up the sides of the machine.

Step 4

After roughly 5 minutes of processing, the ground hazelnuts should start to thicken up, turning into a paste. Continue processing, for another 4 to 5 minutes, until you hear more of a "sloshing" sound. When the hazelnut butter is done, it should have a very runny texture, and will drip off of a spoon.

Step 5

You can use this hazelnut butter right away, or you can add up to a 1/2 teaspoon of salt and process briefly, for a salted hazelnut butter. Do not add any liquids to this recipe, like honey, maple syrup, or vanilla extract, as it may cause the hazelnut butter to sieze and could ruin the texture. (See the notes below for a sweet recipe.)

Step 6

Homemade hazelnut butter can be stored in an airtight container in the fridge for at least 1 month, when you only use clean utensils in the jar. Be sure to keep it free from added moisture for the best shelf life.