Potato, Bacon, and Cheese Muffins

Preheat your oven to 375°F (190°C) and grease a muffin tin or line it with paper liners.
In a large bowl, combine the flour, baking powder, salt, pepper, and garlic powder.
In another bowl, whisk together the milk, melted butter, and eggs.
Add the mashed potatoes to the wet ingredients and mix until combined.
Pour the wet ingredients into the dry ingredients and stir until just combined. Be careful not to overmix.
Fold in the crumbled bacon, shredded cheese, and chopped chives or green onions (if using).