Preheat oven to 400 (F) degrees. Slice bread loaf in half lengthwise. Dust off any crumbs.
Combine butter with ranch dip mix powder and mix until thoroughly blended and smooth.
Divide butter mixture in half and spread evenly over each of the two bread halves.
Place both bread halves directly on a centered oven rack and bake for approximately 7-10 minutes **.
Remove from oven and sprinkle parmesan cheese (if using) over bread right away. Cut into strips and serve immediately.
* Ranch Dressing Powder: The package of dressing is about one ounce but for this recipe, I only use half of the contents. If you really, really love ranch flavor, feel free to use the entire package for a stronger Ranch flavor but I only use half of it and save the remaining powder for something else. I recommend trying out half the package and then increase it next time if you feel the flavor wasn't strong enough for your palate. If you do use the entire package, the one stick of butter works fine with it.
** Baking Time: Because ovens vary, keep an eye while baking the breadsticks to prevent burning them. I recommend checking for doneness at the 7 minute mark. You'll want to make sure the butter has melted through before removing from the oven but you'll also want to look at the bottom of the loaves. They should have a light golden browning to the bottoms and the edges when ready.