Preparation Steps

• Line two baking sheets with parchment paper. In a medium bowl, whisk together the flour, pistachio pudding mix, baking powder, baking soda, and salt; set aside.
• In a large bowl, beat the softened butter with the brown sugar and granulated sugar on medium speed until light and fluffy, 2 to 3 minutes. Mix in the vanilla, scraping the bowl as needed.
• Add the egg and beat just until the mixture looks smooth and slightly glossy, about 30 to 45 seconds (avoid overmixing here).
• Add the dry ingredients in two additions on low speed, mixing only until no dry streaks remain. Fold in the white chocolate chips by hand with a spatula.
• Let the dough rest for 10 minutes to hydrate (this helps the cookies bake thicker). Meanwhile, prepare a #40 scoop or a heaping tablespoon for portioning.
• Scoop 1½-tablespoon mounds of dough onto one prepared sheet, spacing about 2 inches apart, and lightly press each mound to roughly 3/4-inch thickness. Place the sheet in the freezer for 10 minutes. While the dough chills, preheat the oven to 350°F (180°C).
• Bake on the center rack for 12 to 13 minutes, rotating the pan halfway through, until the edges look set and the centers appear slightly underdone.
• Tap the pan once on the counter to settle the cookies. If you like, press a few extra white chocolate chips on top for a bakery finish. Cool on the pan for 5 minutes, then transfer to a rack to cool completely. Repeat with remaining dough, keeping scoops chilled between bakes.