Method

• 01
  Sift together flour and baking soda and set aside. In the bowl of a standing electric mixer fitted with the paddle attachment, cream butter until lemony yellow, about 2 minutes. Scrape down sides of bowl and paddle. Add sugar, brown sugar and salt. Continue creaming mixture on medium speed until it is smooth and lump free, about 1 minute. Stop mixer and scrape down sides of bowl and paddle.
• 02
  Add egg and vanilla and beat on low speed for 15 seconds, or until they are fully incorporated. Do not over-beat. Scrape down sides of bowl and paddle.
• 03
  On low speed, add sifted flour mixture. Beat slowly until all of the flour is incorporated. Scrape down sides of bowl. Add chocolate chunks and mix in.
• 04
  Heat oven to 350℉ with the rack positioned in the lower third of the oven. Line 2 baking sheets with parchment. Spoon heaping teaspoons of dough 2 inches apart onto baking sheets. If not baking right away, remove small handfuls or spoonfuls of dough from mixer and plop them down on the middle of a sheet of parchment or wax paper, creating a log about 1 1/2 inches wide and 12 inches long. Fold parchment over, creating a sausage. Chill for at least 1 hour, preferably overnight. Using a serrated knife, slice chilled dough into 1/3-inch-thick rounds and place them 2 inches apart, in staggered rows, on parchment-lined sheets and proceed. (Dough will keep nicely, tightly wrapped, in the refrigerator for 1 week, or in the freezer for up to 1 month. Thaw frozen dough at room temperature for 30 minutes before slicing.)
• 05
  Bake one sheet at a time for 12 to 15 minutes, until lightly browned, rotating the baking sheet front to back halfway through. Remove from heat and slide parchment off baking sheet and onto a work surface. Allow cookies to cool for at least 5 minutes before serving, or for at least 20 minutes before storing in an airtight container. They will keep for up to 3 days at room temperature.