Cream the butter and brown sugar with a hand mixer on medium speed until light and fluffy, about 2 minutes.

Add the egg and vanilla, then beat on low just until combined.

Mix in the flour, baking soda, and salt on low speed or by hand until no dry flour remains. Do not overmix.

Scoop the dough into 1 1/2 tablespoon balls, roll into smooth rounds, then coat each in the granulated sugar. Place 2 inches apart on a parchment-lined baking sheet.

Bake at 350°F (175°C) on the middle rack for 10 to 12 minutes, until edges are set and centers look soft and puffed.

Let the cookies rest on the hot baking sheet for 5 minutes, then transfer to a wire rack to cool completely.