Step 1

Coarsely crush or chop 1/2 cup unsalted pistachios.

Step 2

Cut 1 stick cold unsalted butter into cubes and place in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Add 3/4 cup granulated sugar. Beat with the paddle attachment on medium-low speed until light and fluffy, 4 to 5 minutes. Stop the mixer and scrape down the sides of the bowl with a flexible spatula.

Step 3

Add 1 cold large egg and 1/4 teaspoon kosher salt and beat on medium speed until combined, about 1 minute. Scrape the sides of the bowl down again. Add 1/2 teaspoon or almond or pistachio extract and beat for 10 seconds. The mixture will be light and fluffy. Scrape the sides of the bowl down one more time.

Step 4

Place 2 cups all-purpose flour, 1/4 cup dry milk powder, and 1/2 teaspoon baking soda in a medium bowl and whisk to combine. Add half to the butter mixture and beat on medium-low speed until almost combined. Add the remaining flour mixture and beat until just combined. Add the pistachios and beat until just evenly distributed.

Step 5

Prepare a 12x16-inch sheet of parchment paper (you can reuse the sheet of parchment you used for mixing the dough). Transfer the dough onto the parchment and shape into a log that is about 12 inches long and about 2 1/2 inches wide. Position the log along one long end, then wrap the log up in the parchment. Wrap the roll with plastic wrap. Refrigerate (place it on a baking sheet first if your refrigerator has wire shelves) for at least 4 hours or up to overnight.

Step 6

Arrange 2 racks to divide the oven into thirds and heat the oven to 350ºF. Line 2 baking sheets with parchment paper.

Step 7

Unwrap the cookie dough log and place on a cutting board. Using a sharp knife, cut the log crosswise into about 3/8-inch thick rounds. Place up to 16 cookies on each baking sheet, spacing them at least 1 inch apart. The cookies won’t spread too much during baking.

Step 8

Bake for 5 minutes. Rotate the baking sheets between racks and from front to back. Bake until lightly golden brown on the edges, about 5 minutes more. Let the cookies cool on the baking sheets for 5 minutes. Transfer to wire racks and let cool completely, the cookies will firm up as they cool.

Step 9

Fit a medium heatproof bowl over a small saucepan of barely simmering water. The water should not touch the base of the bowl. Add 3/4 cup white chocolate chips to the bowl and stir with a flexible spatula until melted and smooth. Turn the heat off.

Step 10

Dip the cookies into the chocolate one at a time: Dip half the cookie into the chocolate, then tap the cookie gently to let the excess chocolate drip back into the bowl. Return to the rack and let sit until the chocolate sets, about 15 minutes.