01 - Preheat oven to 400°F. Cover baking sheet with parchment paper.
02 - Pierce each potato several times with a fork. Position potatoes directly on the oven rack and bake for 45 to 50 minutes until tender. Allow to cool slightly before handling.
03 - While potatoes bake, steam chopped broccoli florets in a steamer or saucepan for 3 to 4 minutes until just tender and vibrant green. Set aside.
04 - Slice cooled potatoes lengthwise. Carefully scoop out most of the flesh with a spoon, leaving a 1/4-inch wall for each shell. Reserve potato flesh for another purpose.
05 - Brush both sides of each potato shell with melted butter. Arrange skins skin-side up on prepared baking sheet. Sprinkle evenly with garlic powder, salt, and pepper.
06 - Bake potato shells for 10 minutes to crisp. Flip each and bake for an additional 5 minutes.
07 - In mixing bowl, combine steamed broccoli, Alfredo sauce, half of the mozzarella, and half of the Parmesan. Mix until evenly distributed.
08 - Spoon broccoli-Alfredo mixture into each crisp potato shell, mounding slightly. Top evenly with remaining mozzarella and Parmesan.
09 - Return filled potato skins to oven and bake for 10 to 12 minutes until cheese is melted and bubbling.
10 - Sprinkle with chopped parsley if desired. Serve hot.