Drain and rinse hazelnuts and place in food processor or high-powered blender. Blend until smooth, scraping down the sides as needed. Depending on the strength of your blender, this may take 10-15 minutes to get the desired consistency.
Once the hazelnuts turn into a buttery consistency, add the sweetener, vanilla, salt, and cacao powder and blend until smooth. Slowly add almond milk until desired consistency.