Preheat the oven to 350°F and line a baking sheet with parchment paper.

In a large bowl, beat the softened butter, brown sugar, and granulated sugar until creamy and smooth

Beat in the egg then mix in the vanilla extract until combined.

Combine the dry ingredients to make the flour mixture. In a separate bowl, whisk together the flour, baking soda, salt, and ground cinnamon.

Slowly add the dry ingredients to the wet mixture and stir until combined. Be careful not to overmix.

Fold in the oats, raisins, and other add-ins using a spatula.

Using a cookie scoop or tablespoon, drop cookie dough balls onto the prepared baking sheet, spacing them about 2 inches apart. Slightly flatten each dough ball with your hand.

Bake for 10-12 minutes, or until the edges are golden brown but the centers are still soft. Be careful not to overbake, as this ensures a chewy texture.

Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.