Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

In a large bowl, beat the softened butter with both sugars until the mixture is light and fluffy, about 3-4 minutes.

Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

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

Gradually add the flour mixture to the butter mixture, mixing on low speed just until combined. Do not overmix.

Stir in the oats and raisins (if using) by hand until evenly distributed.

Cover the dough and refrigerate for at least 30 minutes (or up to 2 days).

Using a cookie scoop or tablespoon, drop rounded portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden but the centers still look slightly underdone.

Allow the cookies to cool on the baking sheets for 5 minutes, then transfer to wire racks to cool completely.

RetryClaude can make mistakes. Please double-check responses.