In the bowl of a stand mixer fitted with the paddle attachment, add the softened butter, brown sugar, and granulated sugar. Beat on medium speed until the mixer is light and creamy, about 2 minutes.

Add the egg and vanilla extract to the bowl. Mix until fully incorporated, then stop and scrape down the sides of the bowl to make sure everything is evenly mixed.

Add the flour, instant pudding mix (just the dry mix-don't prepare it), baking soda, and a pinch of salt. Mix on low speed until a soft, slightly sticky dough forms (about 1 minute).

Using a standard large cookie scoop, portion out the dough and roll it into balls. Gently flatten each one slightly with your hand. These cookies won't spread on their own like a traditional cookie.

Place the shaped cookie dough on a tray, cover, and refrigerate for at least 30 minutes (up to 1 hour). This helps prevent spreading and gives the cookies a thicker, chewier texture.

Preheat your oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat. Arrange the chilled dough balls on the sheet, leaving space between each.

Bake for about 13 minutes, or until the edges look set and the centers still look slightly soft (they'll continue to cook as they cool). Let the cookies rest on the baking sheet for 1 minute, then transfer them to a wire rack to cool completely.