In a medium bowl, whisk together the flour, baking soda, salt, and baking powder. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium speed for 1 minute. Add the granulated sugar (1 3/4 cups) and beat until light and fluffy, about 2 to 3 minutes. I always stop once and scrape down the sides of the bowl with a spatula and continue mixing.
Add the egg, egg yolk, vanilla extract and mix until well combined.
Add the dry ingredients and mix on low until just combined. The dough might look a little crumbly at first, but it will come together and be just fine.
Put the remaining sugar in a small bowl. Form the dough into balls, about 2 tablespoons per cookie. Roll each ball in the sugar until well coated. Place on the prepared baking sheet, about 2-inches apart.
Bake for 10 to 14 minutes or until the bottoms are light golden brown and the cookies start to crack. Check early, every oven is different. Don’t over bake or the cookies won’t be soft and chewy.
Remove the pan from the oven and let the cookies cool on the baking sheet for 5 minutes. Transfer the cookies to a cooling rack and cool completely.
Store the cooled cookies in an airtight container for up to 3 days. You can also freeze the baked cookies for up to 3 months in a freezer bag or container.
Notes
Make sure the butter is softened but not warm or melted. Butter that is too soft can cause the cookies to spread.
Measure the flour by spooning it into a measuring cup and leveling it off. Adding too much flour can make the cookies dry.
Don't overbake the cookies. The centers should still look slightly soft when you take them out of the oven; they will set as they cool.
Store baked cookies in an airtight container at room temperature for up to 3 days, or freeze for up to 3 months. Thaw at room temperature before serving.
To freeze the dough, scoop and roll into balls but don't coat in sugar. Freeze until firm, then transfer to a freezer-safe bag or container. When ready to bake, roll the frozen dough in sugar and bake as directed, adding a few extra minutes to the baking time.