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.
1 cup + 2 Tablespoons (135g) all-purpose flour, ¼ teaspoon baking soda, ½ teaspoon salt
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.
½ cup (113g) unsalted butter, ½ cup + 2 Tablespoons (75g) firmly packed brown sugar, 1 teaspoon grated lime zest
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.
1 large egg yolk, ½ teaspoon vanilla extract, 1 and ½ Tablespoons (23mL) Key lime juice
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.
½ cup finely crushed (120g) graham cracker crumbs, 2 ounces white chocolate (chips or coarsely chopped)
Using a cookie scoop (I use this #50 cookie scoop for all of my standard size cookies), 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.
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.