Brown the butter: Use this post for reference. Set brown butter aside to cool for about 15 minutesStart Timer. It can still be slightly warm, but it should not be hot. 1 cup unsalted butter
Add milk: Stir or whisk in whole milk.
2 Tbsp. whole milk
Mix the wet ingredients: Add the brown sugar and granulated sugar to the brown butter and whisk until well combined. Add the eggs, egg yolk, and vanilla and whisk until smooth and glossy.
1½ cups light brown sugar, 1/2 cup granulated sugar, 2 large eggs, 1 large egg yolk, 2 tsp. vanilla extract
Add the dry ingredients: Add the flour, cornstarch, baking powder, baking soda, cinnamon, and salt. Fold together with a rubber spatula just until no dry streaks of flour remain. Do not overmix.
2¾ cups all-purpose flour, 2 tsp. cornstarch, 1 tsp. baking soda, 1/2- 1 tsp. ground cinnamon, 3/4 tsp. Fine salt, 1 tsp. baking powder
Chill the dough: Cover and refrigerate the cookie dough for about 20-30 minutes Start Timer, or until it's firm enough to easily scoop and roll.
Preheat: Preheat the oven to 350°F. Line a few baking sheets with parchment paper or silicone baking mats.
Scoop: Scoop the dough into ~2 Tbsp. portions and arrange on the prepared baking sheets, leaving about 2 inches between each cookie.
Bake: Bake for ~8 minutes Start Timer. The edges should look just set, while the centers should still look soft and slightly underbaked. Do not overbake! The cookies will continue to bake and set on the hot baking sheet as they cool. They might seem really soft out of the oven; that’s perfect. This is what keeps them soft and chewy!
Shape the cookies: Immediately after removing the cookies from the oven, place a circular cookie cutter or glass slightly larger than the cookie around each one. Gently swirl it in a circular motion to create perfectly round cookies. (I use these!) Allow the cookies to cool on the baking sheet for about 5-10 minutes Start Timer, then transfer to a wire rack to cool completely.
Melt the white chocolate: Melt the white chocolate in a microwave-safe bowl in 20-30 second increments, stirring between each, until completely smooth.
10 oz. white chocolate melting wafers
Dip: Dip about half of each cookie into the melted white chocolate, allowing any excess to drip off. Place on parchment or wax paper.
1/2-3/4 cup finely chopped pistachios
Garnish: While the chocolate is still wet, sprinkle with chopped pistachios. Allow the white chocolate to set completely before serving or storing.