In a medium bowl, whisk together the flour and baking soda. Set aside.
In a large bowl, combine the butter, granulated sugar, and brown sugar. Beat on medium speed until light and fluffy.
Reduce mixer speed to low. Add the salt, vanilla extract, and egg. Beat until well mixed, about 1 minute.
Add the flour mixture to the wet ingredients. Mix until almost combined—do not overmix.
Stir in the rolled oats and chocolate chips with a spatula or wooden spoon until evenly distributed.
Cover and chill the dough in the refrigerator for at least 1 hour, or overnight for best results.
Preheat your oven to 375°F (190°C). Line baking sheets with parchment paper.
Use a small ice cream scoop or two tablespoons to drop heaping tablespoon-sized balls of dough about 2 inches apart on the prepared baking sheets.
Bake for 8 to 10 minutes, or until cookies are golden around the edges but still soft in the center.
Remove from oven and let cookies cool on the baking sheet for 1 to 2 minutes. Then transfer to a wire rack to cool completely.