Wash and poke holes in each potato. Place potatoes on a foil-lined baking sheet. Bake at 400-degrees for 1 hour. Carefully remove potatoes from oven. Let cool for 30minutes.
Cut the potatoes in half lengthwise so you'll have eight halves total. With a spoon, scoop out the insides leaving a ¼- inch in the skin. Place the scooped out potato in a large bowl. Set the potato skins onto a cookie sheet. Mash the potatoes with a fork, then add the broccoli, ranch dressing, sour cream, garlic powder and one cup of the shredded cheddar cheese; mix together well. Divide the mixture into each of the potato skins. Top each with remaining cheddar cheese. Bake an additional 15 minutes, or until cheese is melted. Serve warm and enjoy!