Peel onions, trim the root ends so they will sit upright & cut about 1/2-inch from tops. Rub onions with olive oil & season with salt. Bake for 50 minutes. Remove from oven & allow to cool slightly.
Gently remove the centers leaving a shell of about 2-3 layers. Return a slice of the center to form a bottom. Coarsely chop onion centers.
Filling
In a bowl, combine cream cheese, sour cream, salt, herbs de Provence, garlic powder, minced garlic & chopped onions. Spoon filling into onion shells.
Topping
In a small bowl, combine Panko, butter, cooked bacon & parsley. Spoon carefully over onions.
Bake for 30 minutes or until filling is heated through & bread crumbs start to brown. Serve immediately.