Preheat the oven to 350°F, and line baking sheets with parchment paper.
In a medium bowl, whisk together the flour, baking powder, cinnamon (except for 1 teaspoon), and salt to combine.
2 ½ cups all-purpose flour, 1 tablespoon ground cinnamon, 2 teaspoons baking powder, ½ teaspoon salt
In a large bowl, use an electric mixer to beat the butter, brown sugar, and ¼ cup of granulated sugar until light and fluffy, 2-3 minutes. Scrape down the sides and bottom of the bowl as needed.
1 cup unsalted butter, 1 cup light brown sugar, ¼ cups granulated sugar
Add the egg, the yolk, and vanilla. Beat until combined.
1 large egg, 1 egg yolk, 1 teaspoon vanilla extract
Pour in the flour mixture and mix until combined and no streaks of flour remain.
Place the remaining ¼ cup granulated sugar and 1 teaspoon of cinnamon in a small dish. Using a large (3 tablespoon) cookie scoop, divide the dough into balls. Roll each ball into the cinnamon sugar mixture to coat.
Place the dough balls on the prepared baking sheets, spacing about 2 inches apart. Use the bottom of a heavy bottomed glass to flatten slightly.
Bake for 13-16 minutes, or until the cookies set and begin to brown lightly around the edges.
Cool for 5 minutes before removing to a wire rack to cool completely.
Notes
The calories listed are an approximation based on the ingredients in the recipe card and a serving size of 1 cookie. Actual calories will vary.