In a large bowl whisk together the flour, baking powder, baking soda, and salt until well combined.
Preheat oven to 350°F and prepare 18 muffin cups with non-stick spray, or line with paper liners.
In a medium skillet, heat the butter over medium heat until it foams. Add the leeks and cook, stirring frequently, until they soften, about 8 minutes. Remove the pan from the heat and allow to cool to room temperature.
My favourite food in the whole wide world is toasted buttered bread and sometimes I eat it for every meal of the day. My second favourite food is cheese. I'm left handed and have to use two spatulas to flip pancakes...