Preheat your oven to 350°F (175°C). Line your baking sheets with parchment paper to prevent sticking and ensure even baking.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until the mixture is light and fluffy.

Beat in the eggs one at a time, ensuring each egg is fully incorporated before adding the next. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking soda, salt, and cinnamon. Gradually add this dry mixture to the wet ingredients, mixing just until combined.

Gently fold in the rolled oats and any optional add-ins like raisins or chocolate chips.

Using a cookie scoop or tablespoon, drop rounded spoonfuls of dough onto your prepared baking sheets, spacing them about 2 inches apart. Bake in the preheated oven for 10-12 minutes, or until the edges are golden brown and the centers look slightly underbaked.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.