Preheat Oven: Preheat your oven to 375°F (190°C). Grease a loaf pan or line a baking sheet with parchment paper.
Mix Dry Ingredients: In a large bowl, whisk together flour, baking powder, salt, and garlic powder.
Combine Wet Ingredients: In another bowl, mix milk, egg, and melted butter.
Make Batter: Pour the wet ingredients into the dry ingredients and stir until just combined. Fold in cheddar and Parmesan cheese.
Bake: Pour the batter into the prepared pan and spread evenly. Bake for 20-25 minutes or until golden brown and a toothpick comes out clean.
Cool & Serve: Let it cool for 5 minutes, then slice and garnish with fresh parsley. Serve warm.