Place the butter into a light-colored saucepan. Heat the butter until it browns. Once brown, let it cool to room temperature.
12 tablespoons unsalted butter
Preheat oven to 350°F. Line 2 baking sheets with parchment paper and set aside.
In a medium bowl, whisk the flour, baking powder, baking soda, and salt together.
1¼ cups all-purpose flour, ¾ teaspoon baking powder, ½ teaspoon baking soda, 1 teaspoon kosher salt, ½ teaspoon coarse sea salt
In the bowl of a stand mixer fitted with the paddle attachment, beat the brown sugar and cooled browned butter together until well combined. Add the egg, egg yolk, and vanilla. Mix well.
1 cup dark brown sugar, 1 large egg, 1 large egg yolk, 1 teaspoon pure vanilla extract
Add the dry ingredients to the wet ingredients and mix just until no flour is visible.
Fold in the oats, coconut, cranberries, pistachios, and ¾ cup white chocolate chips. The mixture will be sticky.
1¼ cups old-fashioned rolled oats, ¾ cup sweetened shredded coconut, ¾ cup dried cranberries, ¾ cup shelled roasted pistachios, 1½ cups white chocolate chips
Lightly spray a ¼-cup dry measuring cup with nonstick cooking spray.
Use the measuring cup to scoop the dough. Drop the ¼-cup portions onto the prepared baking sheets, about 2½ inches apart. Space the dough to get 6-8 cookies per sheet.
Bake one sheet of cookies at a time for 14-17 minutes, until edges are set and slightly browned. The centers should be a little puffy and won’t have as much color as the edges. Do not overbake.
Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire cooling rack to completely cool and repeat with any remaining dough.
Make the white chocolate drizzle: If desired, place the remaining ¾ cup of white chocolate chips into a microwave safe bowl. Melt the chocolate chips. Use a spoon to drizzle the melted chocolate over each cookie. Let the chocolate set before serving or storing.