Preparation Steps

• Toast pistachios in a dry skillet over medium heat, stirring often, until fragrant and just starting to color, about 3 to 4 minutes. Let cool.
• In a medium saucepan, whisk together milk, heavy cream, sugar, cornstarch, and salt until smooth. Set over medium heat and cook, whisking constantly, until the mixture is steamy and slightly thickened, 3 to 5 minutes. Do not boil hard.
• Remove from heat. Add white chocolate and butter. Let sit 1 minute, then whisk until completely melted and smooth. Stir in vanilla.
• Add toasted pistachios to a high-speed blender. Pour in half of the warm dairy mixture and blend on high until very smooth, scraping down as needed, 1 to 2 minutes.
• Add the remaining warm mixture and blend again until silky. For an ultra-smooth texture, strain through a fine-mesh sieve back into a clean bowl or jar.
• Press plastic wrap directly onto the surface to prevent a skin, then chill until cool and thickened, about 2 hours. Stir before serving.
• Serve as a spread for toast or croissants, as a filling for crepes and cakes, or drizzled over ice cream.