Heat oven to 350°F. Line two baking sheets with parchment.
Cream the softened butter, brown sugar, and granulated sugar until fluffy, 2–3 minutes.
Beat in the eggs and vanilla until smooth and combined.
Whisk flour, baking soda, salt, and cinnamon in a separate bowl.
Stir the dry ingredients into the butter mixture just until no dry spots remain.
Fold in oats, raisins, and walnuts if using.
Scoop rounded tablespoons of dough onto sheets, spacing about 2 inches apart.
Bake 10–12 minutes, until edges are set and centers look slightly soft.
Cool on the pan 5 minutes, then move cookies to a rack to finish cooling.
Notes
Try orange zest with the raisins, or swap in chopped dried cranberries. For bakery-style thickness, chill the dough 20–30 minutes before scooping. Store airtight at room temperature for 3–4 days or freeze baked cookies up to 2 months.This recipe is an original creation inspired by classic Easy Oatmeal Raisin Cookies flavors. All ingredient ratios and instructions are independently developed.