Prepare a 12 inch muffin pan by generously spraying with non-stick spray. Preheat the oven to 400F.
In a big mixing bowl, add flour, cornmeal, sugar, baking powder, baking soda and salt. Whisk well.
Make a well at the centre. add melted cooled down butter, buttermilk, beaten eggs. Mix with a spatula until eveything is mixed well and no streak of dry flour remaining. Don't overmix.
Spoon the batter into 12 muffin cups, filling just 3/4 of the tin.
Bake in a preheated oven for 20-22 minutes.
Remove the tin from oven, brush with more butter (optional).