Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
Add the egg and vanilla extract to the butter mixture, and mix until well combined.
In another bowl, whisk together the rolled oats, all-purpose flour, baking soda, and salt.
Gradually add the dry mixture to the wet ingredients, mixing until just combined. Be careful not to overmix.
Fold in the chocolate chips, ensuring they are evenly distributed throughout the dough.
Using a cookie scoop or spoon, drop rounded tablespoons of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the edges are golden brown. The centers may look slightly underbaked; they will firm up as they cool.
Remove from the oven and let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.