Preheat the oven to 350℉ and line a baking sheet with parchment paper. Scatter the almonds onto the sheet and roast for 10-15 minutes or until golden brown, fragrant, and toasted. Remove the pan from the oven and allow to cool slightly (you don't want any condensation to form in the blender, otherwise the nut butter will seize!)
Place the almonds in the bowl of a food processor fitted with a blade attachment. Allow the machine to run until a nut butter forms, scraping down the sides every few minutes. The almonds will turn from a crumbly flour to a thick paste to a crumbly ball, then they will gradually form nut butter (this process can take up to 10-15 minutes). The longer you process it, the runnier the butter will be.
Once a nut butter forms, blend in the salt and gradually stir in any add-ins of choice, tasting as you go. Scrape the almond butter into an airtight container or jar and store at room temperature (or in the fridge) for around a month.The butter will firm up if stored in the fridge, but this is normal.