Whisk together flour (2 1/2 cups), baking soda (3/4 teaspoon), and salt (1/2 teaspoon) in a small bowl; set aside.
Add butter (1 cup) and sugars (1/2 cup granulated + 1/2 cup brown) to a large bowl. Using an electric mixer cream mixture until light and creamy. Add egg (1), and vanilla extract (1 teaspoon), and mix until smooth. Gradually add flour mixture until combined. Stir in the lemon zest (3 tablespoons) and white chocolate chips (11 ounces) and mix until both are evenly distributed in the batter.
Roll dough into ping pong-sized balls. Place on a Silpat lined cookie sheet. Flatten slightly (by about 1/3). Bake in preheated oven for 10-12 minutes or until cookies are just beginning to brown slightly on the bottom. Do not overbake or they'll be dry. Allow cookies to cool for a few minutes on the cookie sheets then transfer cookies to the baking rack to cool completely. Store in an airtight container.
Notes
Mixer: This recipe produces a fairly thick dough so definitely use a handheld electric mixer for mixing.
Baking: Pull the cookies out when they're just beginning to brown around the edges. Give them a minute on the sheet if they seem a little gooey in the middle.