Preheat oven to 375F/190C. Generously grease an 8 x 4 inch loaf pan with butter and/or line with parchment paper. You can also use a 9 x 5 inch pan.
In a large bowl combine flour, baking powder, salt, cheddar cheese and Parmesan cheese. Make a well in the center.
Pour milk into well and stir slightly. Add melted butter and mix until just combined. Do not over mix. Spread batter into prepared pan and bake for 40-45 minutes or until lightly browned and toothpick inserted comes out clean.
Brush top with a little melted butter. Cool 10 minutes in pan before transferring to rack to cool completely.