Start by grinding ½ cup of shelled pistachios into a fine powder using a food processor. Be careful not to over-process, or they’ll turn into pistachio butter.

In a medium saucepan, heat 1 ½ cups of whole milk over medium heat until it’s steaming but not boiling. Add the ground pistachios and stir to combine. Remove the saucepan from the heat and let the mixture steep for 15 minutes to infuse the milk with pistachio flavor.

After steeping, strain the milk through a fine-mesh sieve into a clean bowl or measuring cup. Press on the solids to extract as much flavor as possible, then discard the leftover pistachio pieces.

In a medium bowl, whisk together 4 large egg yolks, ½ cup of granulated sugar, and 3 tablespoons of cornstarch. Whisk until the mixture is pale, thick, and smooth. This step ensures the custard will thicken properly.

Gradually pour the warm pistachio milk into the egg mixture, whisking constantly. This process, called tempering, prevents the eggs from curdling. Once all the milk is incorporated, return the mixture to the saucepan.

Place the saucepan over medium heat and cook the mixture, stirring constantly with a whisk or silicone spatula. As it heats, the mixture will begin to thicken. Keep stirring to prevent lumps from forming.

Once the cream reaches a thick, pudding-like consistency and coats the back of a spoon, remove it from the heat. This should take about 5-7 minutes. Stir in 2 tablespoons of unsalted butter and 1 teaspoon of vanilla extract until the butter is fully melted and incorporated.

Strain the crème pâtissière through a fine-mesh sieve into a clean bowl to ensure it’s perfectly smooth. This step removes any small lumps or bits of cooked egg.

Cover the surface of the cream directly with plastic wrap to prevent a skin from forming. Let it cool to room temperature, then transfer it to the fridge to chill for at least 2 hours.

When you’re ready to use the crème pâtissière, give it a quick whisk to restore its smooth texture. If it feels too thick, you can loosen it with a splash of milk or cream.

For a beautiful finishing touch, garnish the cream with chopped pistachios and a drizzle of melted white chocolate. Serve it as a filling for pastries, a topping for desserts, or enjoy it on its own!