Preheat the oven: Set your oven to 350°F (175°C). Line baking sheets with parchment paper.
Mix dry ingredients: In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
Cream the butter and sugar: In a large bowl, beat the softened butter and sugar together until light and fluffy, about 2–3 minutes.
Add egg and vanilla: Mix in the egg and vanilla extract until well combined.
Combine with dry ingredients: Slowly add the dry mixture to the wet ingredients. Mix just until the dough comes together.
Shape the dough: Scoop out tablespoon-sized amounts and roll them into balls. If desired, roll each ball in extra sugar for a sparkly finish.
Place on baking sheet: Space the cookies 2 inches apart on the prepared baking sheet.
Bake the cookies: Bake for 9–11 minutes, or until the edges are just golden and the centers look slightly underdone.
Cool on the sheet: Let the cookies cool on the baking sheet for 5 minutes before moving them to a wire rack.
Serve and enjoy: Eat warm or cooled—either way, these cookies are soft, chewy, and totally satisfying.