Preheat your oven to 180℃
Combine flour, baking soda, salt and whisk until incorporated. Set aside.
In a food processor blitz sugar and basil leaves until the leaves are finely ground and is bright green. Set aside.
In a stand mixer or with an electric mixer, beat butter for about a minute on medium speed until fluffy and pale.
Add the basil sugar to the butter and beat for another 2 to 3 minutes until light in color and creamy.
Add vanilla extract, lemon zest, the egg and the egg yolk into the creamed butter/sugar mixture and beat for 2 to 3 minutes or until the mixture is well combined.
In batches, add the flour mixture to the wet mixture and blend on low speed until barely combined.
Using a 2 tablespoon cookie scoop, measure out cookie dough onto a parchment lined tray.
Make the basil sugar for rolling and gently roll the cookie dough lightly in the sugar.
Place 5 to 6 balls of dough on the baking tray, leaving about 2 inches or more of space between each and bake for 8 to 9 minutes or just until the edges or the cookie are set. . It’s okay if they look slightly under baked in the center, they will firm up as they cool. While the cookies are still hot, scoot them with a cookie cutter to get round cookies.
Let the cookies cool for 5 to 10 minutes and enjoy!