Using a hand mixer in a mixing bowl, cream the butter and brown sugar together on medium speed until smooth and well-blended, about 2-3 minutes.

Add the eggs and mix on high until combined, about 1 minute. Use a rubber spatula to scrape the sides and bottom of the bowl. Add the vanilla and molasses and mix on high until combined. Set aside.

In another large bowl, whisk the flour, baking soda, cinnamon, and salt together. Add to the wet ingredients and mix on low until combined.

Beat in the oats, cranberries, and walnuts (optional) on low speed. Note the dough will be slightly sticky. Chill the dough for 30-45 minutes in the refrigerator.

Preheat oven to 350°F (177°C). Line two large baking sheets with parchment paper.

Using a melon scoop, scoop up some dough and roll into balls of dough. Place the balls two inches apart on the lined baking sheets.

Bake for 12-14 minutes until lightly browned on the sides.

Remove from the oven and let cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.