Preheat oven to 400-degrees.
Add butter and onion to a small frying pan and cook on medium heat. Sauté for 2-3 minutes. Add bacon and continue cooking for 2-3 minutes.
Spoon onion mixture into a 9×13-inch glass baking dish. Add potatoes and pour in vegetable broth, making sure to come halfway up the sides of the potatoes. Sprinkle with salt and pepper. Bake for 1 hour, or until potatoes are golden brown.
Remove from oven and garnish with parsley, if desired. Serve hot.