Set your oven to 350°F (175°C). Line a baking sheet with parchment paper for easy cleanup.

In a large bowl, stir the peanut butter and brown sugar together until smooth and creamy.

Mix in the egg, vanilla, baking soda, and salt. Stir until everything is well blended. The dough will be thick.

Stir in the rolled oats until they’re mixed in evenly. The dough will be chunky and sticky.

Spoon out about 1½ tablespoons of dough for each cookie and place them on your baking sheet. Leave space between them.

Bake for 8 to 10 minutes. The edges should be lightly golden and the centers just set. Don’t overbake—they’ll firm up as they cool.

Let the cookies sit on the pan for a couple of minutes, then move them to a cooling rack. Enjoy them warm or after they’ve cooled down!