Source: Joy the Baker
1 1/2 cup (1 1/2 sticks) unsalted butter, melted and browned to about 3/4 cup butter
1/2 cup granulated sugar
1 cup brown sugar
1 tablespoon pure vanilla extract
2 cups all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1 large egg
1 large egg yolk
1/4 cup toasted coconut, unsweetened or sweetened
1 cup dark chocolate chunks
Place a rack in the center and upper third of the oven and preheat to 350 degrees F. Line two baking sheets with parchment paper. On one baking sheet, spread out shredded coconut. Toast coconut for about 6 minutes, until browned and fragrant. Remove from the oven, place in a small bowl and let cool.
Melt butter in a medium saucepan over medium heat. The butter will begin to foam and crackle. That’s a great sign. That means that the water is evaporating from the butter. Once the crackling subsides, keep an eye on the butter. The butter solids will begin to brown. You’ll smell the butter as it browns. Once well browned, immediately remove the butter from the flame and place in a small bowl. Removing the butter from the pan will ensure that it doesn’t continue to cook and burn in the hot pan. Allow the butter to cool for a few moments.
In a medium bowl, whisk together flour, baking soda and salt. Set aside.
In the bowl of an electric stand mixer, fitted with a paddle attachment, measure granulated and brown sugar. Add the brown butter and beat together, on medium speed, for about 2 minutes. The sugar may still look grainy.
Add the egg and egg yolk and beat on medium speed for 2 minutes. The mixture should become silky smooth. Add vanilla extract and beat.
With mixer on low speed, add the dry ingredients. Beat until just incorporated. Remove the bowl from the mixer and use a spatula to fold in the toasted coconut and chocolate chips. Dough will be thick.
Cookies can be baked immediately, or the dough can be left in the refrigerator to chill for 30 minutes.
Spoon balls by the tablespoonful onto the prepared baking sheets. Bake for 10 to 12 minutes, until golden brown but still slightly soft in the center. Remove from the oven. Allow the cookies to cool on the pan for 5 minutes, before removing to a wire rack to cool completely.