01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk flour, baking soda, salt, and ground cinnamon until well blended. Set aside.
03 - In a large bowl, beat the softened butter, brown sugar, and granulated sugar until creamy and smooth using an electric mixer or whisk.
04 - Add eggs one at a time, beating well after each addition. Mix in pure vanilla extract until incorporated.
05 - Gradually stir the reserved dry ingredients into the wet mixture, mixing until just combined.
06 - Fold in old-fashioned rolled oats and raisins, ensuring they are evenly distributed throughout the dough.
07 - Drop heaping tablespoons of dough onto the prepared baking sheets, spacing each approximately 2 inches apart.
08 - Bake in the preheated oven for 10 to 12 minutes, or until edges are golden and centers are set yet still soft.
09 - Remove baking sheets from oven; allow cookies to cool for 5 minutes before transferring to a wire rack to cool completely.