Preheat your oven to 350°F and line a baking sheet with parchment paper.

Add the lemon zest to the sugar and massage it together with your hands. This step is key for that strong lemon flavor.

In a large bowl, beat the softened butter and lemon sugar together for 2 to 3 minutes until light and fluffy.

Add in the eggs and vanilla extract. Beat again for 1 to 2 minutes until smooth and creamy.

In a separate bowl, whisk together the flour, cornstarch, baking powder, and salt.

Add the dry ingredients into the wet and fold gently until almost combined.

Coarsely chop the white chocolate and fold it into the dough until evenly distributed.

Scoop the dough using a medium cookie scoop, roll each ball in the extra granulated sugar, and place on your prepared baking sheet.

Bake at 350°F for 8 to 10 minutes. The edges should look set, but the centers should still look soft.

Let the cookies cool on the baking sheet for 10 minutes, then transfer to a wire rack or enjoy warm.