First, melt the butter and set aside to cool. Mix together the dry ingredients in a large bowl.
In a jug, whisk together the buttermilk, egg, and vanilla extract. Add the liquid to the dry mix and starting lightly mixing together. The secret to thick, fluffy pancakes is not to over mix. My trick is to stir it enough times to spell P.A.N.C.A.K.E, and then stop.
Slowly drizzle in the cooled butter and stir another 3 times. Lumps are ok, resist the urge to mix more. Put in the fridge for 10 minutes. This helps the butter to chill and bubbles to form in your batter. Put a heavy bottom frying pan or griddle on medium heat-low heat. Spoon one big spoon of the batter per pancake.
Cook for roughly 4 minutes on one side. It is time to turn them over when you see bubbles forming on the top of the pancake and the edges turn color (forming bubbles on top is really important because they hold your pancake up and keep it thick, I call them pancake pillars. Flip and cook for another on the other side a little longer, until brown. Enjoy with butter and maple syrup.