Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Spread the hazelnuts evenly on the baking sheet and roast for 8–10 minutes, until the skins begin to crack and the nuts are fragrant.
Transfer the warm hazelnuts to a clean kitchen towel. Rub them together to remove most of the skins.
Add the roasted hazelnuts to a food processor and blend on high, stopping to scrape down the sides as needed. The mixture will go from crumbly to pasty to creamy in 5–7 minutes.
If needed, add neutral oil to reach your desired consistency and blend again until smooth.
Mix in a pinch of sea salt and maple syrup (optional) to taste.
Transfer to a clean jar and store at room temperature for up to 2 weeks, or in the fridge for up to 1 month.