Roast the Pistachios: Preheat your oven to 400°F (200°C). Spread the pistachios evenly on a baking sheet and roast for 6 minutes. Let them cool slightly.
Blend the Pistachios: Add the roasted pistachios to a food processor and blend for 2–3 minutes, scraping down the sides as needed, until a coarse paste forms.
Incorporate the Remaining Ingredients: Add the white chocolate chips, sugar, salt, and water to the pistachio paste. Blend again until smooth.
Adjust Consistency (Optional): If needed, drizzle in the oil at this stage to achieve a creamier, more spreadable consistency. Blend until the mixture is silky and smooth.
Store the Spread: Transfer the pistachio spread to an airtight container and refrigerate. Use as a spread, topping, or dip for your favorite treats!