01 - Preheat the oven to 400°F. Prick potatoes with a fork and bake directly on the oven rack for 50–60 minutes, until tender.
02 - Cool potatoes slightly, then slice each in half lengthwise. Carefully scoop out the insides into a bowl, leaving a 1/4-inch shell.
03 - Add cream cheese, sour cream, butter, garlic powder, salt, and pepper to the potato flesh. Mash until smooth.
04 - Stir in diced jalapenos, green onions, half the cheddar cheese, half the mozzarella, and half the bacon (if using).
05 - Spoon the mixture back into the potato skins. Top with remaining cheeses and bacon.
06 - Place potatoes on a baking sheet and bake at 400°F for 15–20 minutes, until hot and tops are golden.
07 - Garnish with extra jalapenos and chives before serving.