Position a rack in the middle of oven; preheat to 350°.
Grease several large baking sheets or coat with nonstick spray.
In a large bowl, vigorously stir the brown sugar into the butter until well blended, mashing out any sugar lumps with the back of a spoon.
Stir in the egg, vanilla, salt, and baking soda until thoroughly incorporated.
Stir in the flour and morsels just until evenly incorporated.
Vigorously stir in the eggs, then the oats; let stand for 5 minutes so the oats can hydrate.
Drop the dough with a 1 1/2-inch spring-loaded scoop or heaping measuring tablespoonfuls, spacing about 2 inches apart.
Bake one sheet at a time for 8-12 minutes or until the cookies are barely tinged and almost firm when pressed in the middle; be careful not to over bake.
Transfer the baking sheets to wire racks; let stand until the cookies firm up just slightly, about 2 minutes.
Using a wide spatula, transfer the cookies to the wire racks; let cool completely.