Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats.
2. Cream butter and sugars: In a large bowl, beat the softened butter, brown sugar, and granulated sugar together with a hand mixer or stand mixer on medium speed for about 2 minutes until smooth and creamy.
3. Add wet ingredients: Add the eggs one at a time, mixing well after each. Stir in the vanilla extract.
4. Mix in dry basics: Add the baking soda, salt, and all-purpose flour. Mix on low speed just until combined.
5. Fold in oats & chocolate: Add the rolled oats and chocolate chips. Mix with a spatula or wooden spoon until evenly distributed throughout the dough.
6. Scoop: Roll or scoop the dough into 1.5-tablespoon balls (a medium cookie scoop works great) and place them about 2 inches apart on the prepared baking sheets.
7. Bake: Bake at 350°F for 9 to 11 minutes, or until the edges are lightly golden and the centers still look slightly soft/underbaked.
8. Cool: Remove from the oven and let the cookies sit on the hot baking sheet for 5 minutes (they will finish setting up). Transfer them to a wire rack to cool completely.