Preheat oven to 400 degrees Fahrenheit
Scrub potatoes clean and prick with fork to allow steam to escape during baking
Bake potatoes for one hour (up to one hour and 30 minutes) or until a butter knife can easily pierce through the potato.
Cook bacon in skillet and set aside
Discard all but 1 tbsp of bacon fat
Add white part of green onions to bacon fat, cook until translucent.
Add garlic to skillet, cooking for 1 minute. Do not burn
Remove from heat and transfer onion and garlic mixture to small bowl
Chop bacon into small bits and pieces. Reserving some for garnish.
Remove potatoes from oven when done
Cut potatoes in half lengthwise
Scoop out flesh of potatoes into mixing bowl leaving 1/4 inch around shell of potato
Mash potatoes until nice and fluffy
Add the melted butter and the onion-garlic bacon fat mixture to the mixing bowl
Add the bacon, the sour cream, and the parmesan and cheddar cheeses. Reserve a few sprinkles of the bacon and cheeses for later.
Mix together until well combined. Spoon the mixture back into the potato shells evenly
Sprinkle remaining cheeses and bacon over the potatoes and return to the oven
Continue to bake until heated throughout, approximately 15 minutes and remove from the oven
Garnish with sliced green onion and serve