Step 1

Adjust the oven racks to the upper- and lower-middle positions and preheat oven to 325 degrees F. Line 2 baking sheets with parchment paper.

Step 2

In a medium bowl, whisk together the flour, baking soda, and salt.

Step 3

Using an electric mixer on medium speed, beat the butter and sugars until thoroughly blended, 2 to 3 minutes. Beat in the egg, yolk, and vanilla until combined. Reduce the mixer speed to low, add the dry ingredients and beat until just combined. Using a rubber spatula, stir in the chocolate chips.

Step 4

Roll a scant ¼ cup of the dough into a ball. Hold the dough ball with the fingertips of both hands and pull into 2 equal halves. Rotate the halves 90 degrees and, with jagged surfaces facing up, join the halves together at their base, again forming a single ball, being careful not to smooth the dough's uneven surface. Place the formed dough balls on the prepared baking sheets, jagged surface up, spacing them 2½ inches apart.

Step 5

Bake until the cookies are light golden brown and the outer edges start to set, yet the centers are still soft and puffy, 15 to 18 minutes, rotating the baking sheets front to back and top to bottom halfway through the baking time. Cool the cookies on the baking sheets. Once cool, store in an airtight container at room temperature for up to 4 days. These can also be wrapped in plastic wrap, placed in a freezer bag and frozen for up to 2 months.