Follow these straightforward steps to create your own Levain Bakery NYC Cookies:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
2. Cream the Butter and Sugars: In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
3. Add Eggs and Vanilla: Beat in the eggs, one at a time, followed by the vanilla extract until combined.
4. Combine Dry Ingredients: In another bowl, whisk together the flour, salt, baking powder, and cornstarch until evenly mixed.
5. Combine Mixtures: Gradually add the dry ingredients to the wet ingredients and mix until just combined. Be careful not to overmix.
6. Fold in Chocolate Chips and Nuts: Gently fold in the chocolate chips and walnuts (if using) until evenly distributed in the dough.
7. Form Cookie Dough Balls: Using a large ice cream scoop or your hands, form generous dough balls (about ¼ cup each) and place them on the prepared baking sheets, spacing them about 2 inches apart.
8. Bake: Bake the cookies in the preheated oven for 12-15 minutes, or until the edges are golden but the centers remain soft.
9. Cool on Baking Sheets: Allow the cookies to cool on the baking sheets for about 10 minutes before transferring them to wire racks to cool completely.

With these easy steps, you’ll create cookies that are not only impressive in size but also bursting with flavor.