Preheat oven to 350°F and line two baking sheets with parchment paper.
In a large mixing bowl, beat together butter, brown sugar, and granulated sugar until creamy and smooth, about 2-3 minutes.
Add eggs and vanilla extract, beating until well incorporated.
In a separate bowl, whisk together flour, baking soda, cinnamon, and salt.
Gradually stir the dry ingredients into the wet mixture until just combined.
Fold in the oats and raisins, stirring until evenly distributed throughout the dough.
Drop heaping tablespoons of dough onto prepared baking sheets, spacing them about 2 inches apart.
Bake for 11-13 minutes until edges are lightly golden but centers still look slightly soft.
Cool on baking sheet for 5 minutes, then transfer to a wire rack to cool completely. Store in an airtight container for up to a week.