Whisk flour, sugar, baking powder and the salt in a medium bowl.
Warm milk until lukewarm.
Whisk milk, egg, melted butter, and the vanilla extract until combined. (By warming the milk slightly, the melted butter mixes into the milk instead of turning into small lumps).
Make a well in the center of the flour mixture, pour milk mixture into the well and use a fork to stir until you no longer see clumps of flour. It is okay if the batter has small lumps - it is important not to over mix the batter.
Lightly brush skillet with melted butter. Use a 1/4 - cup measuring cup to spoon batter onto skillet. Gently spread the batter into a 4 inch circle.
When edges look dry, and bubbles start to appear and pop on the top surfaces of the pancake, turn over. This takes about 2 minutes. Once flipped, cook another 1 to 2 minutes or until lightly browned and cooked in the middle. Serve immediately with syrup & butter.