Preheat the oven to 375°F and lightly grease a baking sheet or line the sheet with parchment paper.

In a mixing bowl, cream together the butter, brown sugar, and granulated sugar.  Stir in the beaten egg and the vanilla extract.

Whisk together the flour, the baking soda, the salt, and the cinnamon.

Add the liquid ingredients to the dry until a soft dough comes together.

Stir the oats into the dough until well combined, then stir in the butterscotch chips until well distributed.

To bake, take walnut-sized balls of dough and place them on the sheet 2 inches apart.

Bake in batches for 7-9 minutes or until the cookies are set and lightly browned on the edges, rotating the sheet once.

After removing from the oven, lightly sprinkle the tops of the cookies with the flaked sea salt.

Cool on a rack for 20 minutes as the cookies will continue to cook after they leave the oven.