01 -
Heat the oven to 400°F. Prick the potatoes with a fork, rub with 2 teaspoons olive oil, and sprinkle with 1/2 teaspoon salt. Bake directly on a sheet pan for 55-65 minutes, until very tender in the center.
02 -
Toss the broccoli with the remaining 1 teaspoon olive oil, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Add it to the pan during the last 15 minutes of potato baking, roasting until tender with lightly browned edges.
03 -
Let the potatoes cool for 10 minutes. Cut each one in half lengthwise and scoop the flesh into a large bowl, leaving about a 1/4-inch border inside each skin.
04 -
Mash the hot potato flesh with butter, sour cream, milk, garlic, Dijon, Parmesan, 1 cup cheddar, the remaining salt and pepper, and chives. Chop the roasted broccoli small and fold it in. Add another splash of milk only if the filling feels stiff.
05 -
Place the potato skins back on the sheet pan. Divide the filling among the shells and mound it gently. Sprinkle the remaining 1/2 cup cheddar over the tops.
06 -
Bake at 400°F for 12-15 minutes, until the potatoes are hot through and the cheese is melted with golden spots. Rest for 5 minutes, then finish with more chives.