Preheat the oven to 350°Fahrenheit/175°Celsius and line a baking sheet with parchment paper.
In a large bowl or in a stand mixer bowl fitted with the whisk attachment, whisk the sugar with the lemon zest until the sugar turns a very pale yellow. You can also do this with your hands instead. You want to release the lemon oils from the zest to make lemon sugar.
Add the room temperature butter and beat on medium-high speed with a handheld mixer or a stand mixer fitted with the paddle attachment until light and fluffy - about 3-4 minutes.
Add the egg, vanilla extract, lemon extract and lemon juice. Beat on medium-high speed until well combined. Make sure you scrape down the sides of the bowl so everything is getting evenly mixed.
Add in the flour, baking soda, baking powder and salt and mix on low speed until just combined.
Pour in the chopped chocolate and stir it into the cookie dough.
Scoop out 3 tablespoons of dough and roll into a ball. Place the cookie dough balls on your baking sheet. If your baking sheet can't fit all 9 cookie dough balls with a few inches between each one, place just 6 on the baking sheet and put the others in the fridge.
Bake in the preheated oven for 10-12 minutes. The sides should have set and turned very light brown. Let the cookies cool on the baking sheet before enjoying!
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. Butter: I use European style butter in my recipes. This will make your finished bake much creamier and richer.Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt. Please note I am using Diamond Crystal Kosher Salt and not Morton Salt, which is a coarse kosher salt. Coarse kosher salt is much too salty for this recipe. White Chocolate: I used a chopped up chocolate bar here, but you can also use chocolate chips if you prefer! Bakery Style Cookies: Keep a small handful of chopped chocolate to the side. As soon as the cookies are out of the oven, use a biscuit cutter to scoot the cookies into a perfect circular shape. Gently press the extra chopped chocolate on top. Storage: keep the baked cookies in a tupperware for up to 1 week at room temperature. Freeze unbaked cookie dough balls for up to 2 months. When ready to bake, take them out of the freezer and bake at the same temperature as above but for an extra minute or two.