Step 1

Preheat the oven to 350°F and line two baking sheets with parchment paper.

Step 2

Cut the butter into cubes and place in a large mixing bowl. Add the sugar and lemon zest and beat with an electric mixer on medium speed until fluffy, about 3-4 minutes.

Step 3

Scrape the bottom and sides of the bowl and turn the mixer to low. Beat in the egg, yolk, vanilla, and lemon juice until evenly mixed. It’s okay if it looks a bit curdled.

Step 4

In a separate bowl, sift the flour, cornstarch, baking powder, baking soda, and salt. Gently mix into the wet mixture, stirring until about halfway combined. Add 1 1/2 cups of chocolate chips and mix gently just until the dough forms.

Step 5

Drop 2 tablespoonfuls of dough onto the prepared baking sheets, spacing each potion about 2 inches apart. (Chill unusued dough until ready to bake.)

Step 6

Bake for 10-12 minutes, or until the edges are lightly golden. Remove from the oven and immediately press the remaining chocolate chips into the tops of the hot cookies.

Step 7

Let cool for 5 minutes before transferring to a wire rack to cool completely. Enjoy!