Step 1: Preheat your oven to 350°F (175°C).
Step 2: In a large mixing bowl, cream together the softened butter, white sugar, and brown sugar until light and fluffy.
Step 3: Mix in the vanilla extract and the whisked eggs until well combined.
Step 4: In a separate bowl, whisk together the flour, baking soda, salt, and cinnamon.
Step 5: Gradually add the dry mixture to the wet ingredients, stirring gently until just combined.
Step 6: Fold in the rolled oats and chocolate chips or diced chocolate bars.
Step 7: Drop rounded balls of dough onto prepared baking sheets, leaving space between each cookie.
Step 8: Bake for 10-12 minutes, or until the edges are lightly golden.
Step 9: Let cool on the baking sheets for about 5 minutes before transferring to a cooling rack.
