Preheat your oven to (350°F) = (176°C). Grease a 12-cup muffin tin or line the cups with paper liners. Combine the flour, sugar, baking powder, and salt. Set the bowl aside. Now, combine the liquids, milk, eggs, oil, and butter and stir until smooth. Grab a larger bowl and mix the wet and dry ingredients together. Use a spatula to mix them ever so softly. Not too much, just enough. Do not overmix the batter. Scoop the batter evenly into the muffin cups. Sprinkle the tops with coarse sugar, you will love the look and the taste. Bake for 20 minutes or until a toothpick comes out clean. Cool the muffins on a cooling rack.