Preheat Oven: Set to 350 degrees F and line baking sheets with parchment paper.
Mix Dry Ingredients: Combine oats, protein powder, baking soda, cinnamon, and salt in bowl.
Combine Wet Ingredients: Whisk together melted coconut oil, honey, eggs, and vanilla.
Mix Together: Pour wet ingredients into dry mixture, stirring until combined.
Add Mix-Ins: Fold in cranberries and walnuts if using.
Shape: Scoop dough using cookie scoop or spoon. Place 2 inches apart on sheets.
Flatten: Gently press each cookie to about 1/2-inch thickness.
Bake: Bake 10-12 minutes until edges are golden brown.
Cool: Let cool on sheets 5 minutes, then transfer to cooling rack.