Preheat your oven to 350 degrees Fahrenheit. Line rimmed baking sheets with parchment paper and set aside. In a large bowl whisk together the flour, baking soda, and salt. Set aside.
2 1/2 cups all purpose flour, 1/2 teaspoon baking soda, 1/2 teaspoon salt
In a large bowl with a hand mixer or in the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and brown sugar until light and fluffy, about 3 to 6 minutes.
1 1/2 cups light brown sugar, 14 tablespoons unsalted butter
Mix in the molasses. Once combined, add in the egg. After it is combined, add in the egg yolk. Then the vanilla until well combined.
2 tablespoons molasses, 2 teaspoons vanilla extract, 1 large egg, 1 egg yolk
Add the flour mixture to the wet ingredients. Mix on low until it just begins to combine. Then turn up the mixer to high just long enough that you don't see streaks of flour. Scrape down the bowl and on the bottom to ensure that all the flour is added. Only mix long enough to combine the flour.
Using a 1 1/2 tablespoon cookie scoop, roll the dough into one inch sized balls. Roll the balls in granulated sugar. Place on the prepared baking sheet. Space the cookies about two inches apart. 1/3 cup granulated sugar
Bake for 8 to 10 minutes, rotating the pan halfway through the baking, or until the cookies just begin to turn golden brown around the edges. Allow to cool for 2 minutes on the baking sheet before transferring to a wire rack to cool completely.
Once cool, store in an airtight container for up to 2 weeks.