Spread walnuts out on a baking sheet, and toast in oven for 5 minutes
Remove from oven and let cool while making cookies (adding them to dough while hot will melt your chocolate chips)
Stir flour, baking soda, salt, and cornstarch together in a small mixing bowl and set aside
Beat butter and both sugars together until light and fluffy (2-3 minutes)
Beat in egg and vanilla
Stir in dry ingredients until just combined
Then add chocolate chips and walnuts, and stir together
Refrigerate for one hour
Separate dough into 6 balls (they’ll be very big!), and place on cookie sheet at least two inches apart
Press additional chocolate chips on top of cookies if desired
Bake for 10-12 minutes until set on the edges, and no longer wet looking. Go on the short side for gooier cookies, and longer side for more set cookies
Notes
Refrigerating the dough is key to making thick Levain bakery-style cookies, so don’t skip it!You can however speed the process up by making your cookie dough balls first, then popping them in the freezer for 15 minutesThis dough can also be made ahead and refrigerated in an air-tight container for several days until you’re ready to bake