In a medium-sized bowl, blend the flour and baking soda thoroughly; set this aside for later.

In another large mixing bowl, cream together the softened butter and both types of sugar. Beat on medium speed until the mixture becomes light and airy.

Lower the mixing speed and incorporate the salt, vanilla extract, and egg. Continue beating until everything is well blended, which should take about a minute.

Gradually add the flour mixture to the wet ingredients, mixing just until almost fully combined.

Gently fold in the rolled oats and chocolate chips until evenly distributed throughout the dough. Allow the dough to chill in the refrigerator for at least one hour, or preferably overnight.

When ready to bake, preheat your oven to 375°F (190°C). Line baking sheets with parchment paper.

Using a small ice cream scooper or two tablespoons, drop heaping tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Bake in the preheated oven until the edges of the cookies turn golden brown, but the centers remain soft, about 8 to 10 minutes.

Once baked, remove the cookies from the oven and let them rest on the baking sheet for 1 to 2 minutes. Then transfer them to a wire rack to cool completely.