Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth.

Beat in the eggs one at a time, then stir in the vanilla extract.

In a separate bowl, whisk together flour, baking soda, cinnamon, and salt.

Gradually add the dry ingredients to the wet ingredients and mix until just combined.

Stir in the rolled oats by hand.

Drop rounded tablespoons of dough onto the prepared baking sheet, spaced 2 inches apart.

Bake for 10 to 12 minutes or until the edges are golden brown.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.