Preheat your oven to 350°F (175°C). Spread the hazelnuts in a single layer on a baking sheet and roast them for about 10-12 minutes, or until fragrant and the skins start to loosen.
Remove the hazelnuts from the oven and let them cool slightly. Rub them with a clean kitchen towel or paper towel to remove as much of the loose skins as possible.
In a food processor or blender, grind the roasted hazelnuts until they form a smooth paste. This may take a few minutes, and you may need to scrape down the sides of the processor or blender occasionally.
Add the cocoa powder, maple or honey, salt, oil, and vanilla extract to the hazelnut paste.
Process or blend until all the ingredients are well combined and the mixture is smooth and creamy.
Taste the homemade Nutella and adjust the sweetness or cocoa flavor to your preference by adding more maple/honey or cocoa powder if desired.
Transfer the spread to a jar or airtight container for storage. It can be stored at room temperature for up to 2 weeks.