Preheat the oven to 350°F and line baking sheets with parchment paper.
In a large bowl, cream together the butter, sugar, brown sugar, and pudding mix on medium speed for 2 minutes, until light and fluffy.
Beat in the vanilla and eggs until fully incorporated.
Add the baking soda, salt, cinnamon, oats and flour. Mix just until combined. Do not overmix.
Scoop dough into 3-tablespoon balls and refrigerate for 30 minutes to prevent spreading and create thicker cookies.
Bake for 10–12 minutes, until edges are lightly golden and centers look slightly underbaked.
Allow cookies to cool on the pan for 5 minutes before transferring to a rack.