Preheat your oven to 400°F (200°C). Wash the russet potatoes thoroughly and pat dry. Rub each potato with olive oil and sprinkle with salt. Place directly on oven rack or baking sheet and bake for 45-60 minutes until tender.
Steam broccoli florets until bright green and just tender, about 4-5 minutes. Drain and set aside.
When potatoes are cool enough, slice each in half lengthwise. Scoop out fluffy potato flesh into a large mixing bowl, leaving a thin border to keep skins intact.
Add steamed broccoli, shredded cheddar cheese, sour cream, milk, garlic powder, salt, and pepper to potato flesh. Mix well until creamy and combined. Adjust seasoning as needed.
Spoon the creamy broccoli cheddar filling back into potato skins, mounding slightly. Arrange on baking sheet and bake another 15 minutes until cheese melts and tops are golden.
Remove from oven and sprinkle with chopped green onions. Serve immediately and enjoy.