You can pick through the candy pieces and use the Halloween colors or just use them all.
If you can't find nut-free candy pieces or don't have them on hand, increase the chocolate and white chips to 1 cup each.
Be sure to read the ingredient labels to make sure the sprinkles are safe.
Do not add the candy eyeballs before baking.
Use quick oats in this recipe. Quick oats are more finely cut whole oats and will give the monster cookies a more uniform texture. Quick oats also act as a binder since the consistency is more powdery. If you don’t have quick oats, pulse your whole oats in the food processor a few times to break them down.
To freeze Monster Halloween Cookies: Baked and cooled cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months too. Bake frozen cookie dough balls for an extra minute, no need to thaw.