1/2cupfinely crushed (120g) graham cracker crumbsabout 8 full sheets
2ounceswhite chocolate (chips or coarsely chopped)(about 1/4 cup)
Preheat the oven to 350ºF (177ºC). Line a large baking sheet with parchment paper or a silicone baking mat. Set aside.
In a medium size bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large size bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, cream the butter, brown sugar, and lime zest on medium speed until light and fluffy, approximately 2-3 minutes.
Turn the mixer down to low, then add the egg yolk, vanilla, and Key lime juice and continue beating until everything is incorporated, scraping down the sides as necessary.
Slowly add the dry ingredients, and continue to mix on low until dough starts to come together. Add the graham cracker crumbs and white chocolate and mix again until everything is evenly dispersed.
Using a cookie scoop, drop rounded balls of dough onto the prepared baking sheet. Bake cookies for 10-12 minutes, or until the edges are set. Remove from oven and allow cookies to cool on the baking sheet for 5 minutes before transferring to a cooling rack to cool completely. Store cookies at room temperature up to 5 days. Rolled cookie dough freezes well, up to 2 months. Place on baking sheet frozen and bake for 11-13 minutes.