Preheat your oven to 350°F (175°C).
In a large bowl, combine the peanut butter and brown sugar until smooth.
Add the egg and vanilla extract, mixing well.
In a separate bowl, whisk together the oats, baking soda, and salt.
Gradually add the dry ingredients to the peanut butter mixture.
Stir until fully combined; the dough will be thick.
If desired, fold in the chocolate chips.
Using a tablespoon, scoop the dough onto a baking sheet lined with parchment paper.
Flatten each cookie slightly with a fork.
Bake for 10-12 minutes or until golden brown.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.