Preheat oven to 350°F (177°C). Line large baking sheets with parchment paper or silicone baking mats and set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a handheld mixer, beat the butter and granulated sugar together for 1-2 minutes or until well combined. Mix in the egg, egg yolk, and vanilla extract until fully combined, stopping to scrape down the sides of the bowl as needed.
In a separate mixing bowl, whisk together the flour, baking powder and salt. Add half of the dry ingredients to the mixing bowl with the wet ingredients and mix until just combined, then add the rest of the dry ingredients and continue mixing until fully combined.
Using a 1.5 tablespoon cookie scoop, scoop balls of cookie dough onto the prepared baking sheets, making sure to leave a little room between each one. Roll into balls and gently press down to slightly flatten the cookie dough.
Bake in separate batches at 350°F (177°C) for 11-13 minutes or until the tops of the cookies are set and the edges are lightly golden brown.
Remove from the oven and cool on the baking sheet for 5-10 minutes, then carefully remove the cookies and transfer to a wire rack to cool completely.
Notes
Store cookies in an airtight container at room temperature for up to one week.Freezing instructions: Cookie dough will freeze well for up to 3 months, thaw overnight in the refrigerator. Baked cookies that have cooled completely will freeze well for 3 months too, thaw to room temperature on the counter before serving.Unsalted Butter: I recommend using unsalted butter in this recipe. If you only have salted butter, just reduce the salt to a tiny pinch or 1/8 teaspoon.Recipe Variations:
Swap out 1/2 teaspoon of vanilla extract for 1/2 teaspoon of almond extract
Dip each cookie in or drizzle with melted white chocolate and sprinkle with crushed candy canes
Mix 1/4 cup to 1/3 cup of sprinkles into the cookie dough
Top the cookies with cream cheese frosting or buttercream frosting