In a large bowl, cream together the butter and sugars until fluffy.
Mix in the egg and vanilla extract, stirring until well combined.
Mix in the flour, oats, cinnamon, and baking soda. Stir until well combined.
Add in the raisins. Stir until just combined.
Cover bowl and refrigerate for at least 30 minutes and up to 24 hours.
When you’re ready to bake, preheat the oven to 350ºF and line baking sheets with parchment paper.
Use a cookie scoop to form dough into balls and place 2 inches apart on the baking sheets.
Bake 9-11 minutes.
Let the cookies cool on the baking sheet for 10 minutes before transferring to a cooling rack to finish cooling.