Melt the butter in a heat-proof bowl in the microwave, or in a small saucepan over a low heat. Allow to cool while continuing to the next step.
¾ cup butter
In a large mixing bowl, combine the white sugar and the lemon zest. Rub the lemon zest into the sugar. This releases the oils and flavoring into the sugar.
1½ tablespoons lemon zest, 1¼ cups white granulated sugar
Add the cooled melted butter to the sugar-lemon mixture and whisk together to combine.
Add in the lemon juice and egg. Whisk vigorously to combine.
1 egg, 4 teaspoons lemon juice
Add half the flour, baking soda, and salt to the butter-sugar mixture. Stir together with a wooden spoon or rubber spatula until fully combined.
Add the rest of the flour and the white chocolate chips to the mixture, and then fold in until all the flour has been incorporated.
1¼ cups white chocolate chips
Line a plate or a baking tray with baking paper or parchment paper. Using a cookie scoop (I used a size 3 or 2 tablespoons cookie scoop). Portion the dough out onto the baking tray. Refrigerate for 25 minutes.
While the cookies are chilling, preheat the oven to 180°C/350°F. Line two large baking trays with baking paper or parchment paper.
Place the chilled cookie dough balls onto the prepared baking tray about 2 to 3 inches apart. Bake for 13-18 minutes. Mine were done at 15 minutes. *Note 4
Allow the baked white chocolate lemon cookies to cool on the cookie sheet for 5 minutes before lifting onto a wire rack to cool completely. If you want you can decorate the cookies with a few more chocolate chips while they are still warm.
All temperatures stated are for conventional ovens. Decrease the temperature by 20°C/25°F or gas mark 1 for "fan" or air-fryers.
Notes
Lemon juice and lemon zest can be replaced with 2 teaspoons of lemon extract.
I also tested this recipe with a total of 1½ cups (300 grams) of white sugar. Which results in a chewier cookie.
If increasing the sugar to 300 grams, then increase the butter to 1 cup or 225 grams.
I don't flatten my cookies before baking, they will flatten and spread during the baking process.
Storage and Freezing
These cookies can be stored in an airtight container for up to a week. Baked cookies can be frozen for up to 3 months.If freezing cookie dough, first scoop out portions. These can then be baked directly from frozen as per the recipe instructions, however, they may not spread as much.