Preheat the oven to 350 degrees and line a baking sheet(s) with parchment paper. Set aside.
In a large bowl, cream butter, brown sugar, and sugar together until combined and creamy.
Mix eggs and vanilla, and beat until combined.
In a medium bowl, whisk flour, baking soda, cinnamon and salt together.
Add dry ingredients to wet ingredients, and mix well.
Stir in oatmeal then gently stir in cranberries, dark chocolate chips, and walnuts.
Drop by heaping teaspoons onto the prepared baking sheet.
Bake for 10-12 minutes or until the cookies start to brown around the edges.
Remove from oven and place on a wire rack to cool completely.