Preheat oven to 350
degrees F (177 degrees C).
oven rack in the top third of the oven, and one oven rack in the bottom third of
the oven. Line
sheets with parchment paper.
In a large bowl,
whisk together the flour, baking soda, and salt.
In the bowl of
your electric mixer (or with a hand mixer), beat the butter and sugars until
light and fluffy (about 2 - 3 minutes). Scrape down the sides of the bowl. Add the egg
and egg yolk, beating until well combined. Beat in the vanilla extract.
Gradually add the flour mixture to the creamed mixture and beat
just until incorporated. Scrape down the sides of the bowl as needed. Stir in
the chocolate chunks.
Form dough into
balls, using 1/4 cup (55 grams) for each cookie. Place six balls of dough on
each baking sheet. Gently flatten each ball of dough into
a 2 1/2 inch (6.5 cm) round. Bake the cookies for about 15-17 minutes,
rotating the baking sheets halfway through the baking time. The cookies are done
when they are light golden brown in color and just set. They will still seem a
little soft but they will firm up as they cool. Remove from oven and let the
cookies cool a few minutes on the baking sheet before transferring them to a
wire rack to cool.
Makes about 18 large cookies.