Sift all the wet ingredients together into a large bowl.
Pour the wet ingredients into the dry ingredients and mix until just combined. Do not over-mix.
Scrape the batter into the prepared sheet pan, and then using an offset spatula, evenly spread the batter. Gently shake the sheet pan to make sure that the batter is evenly spread, but do not shake or knock the pan too hard (as this may deflate the batter).
Place the sheet pan in the center of your oven and bake for 5 - 7 minutes. Check at 5 minutes - the pancakes are done, if the center of the pancake is springy to the touch, and a toothpick inserted into the middle comes out clean.
Remove the pan from the oven and switch the oven to broil. Brush the surface of the pancake liberally with the remaining melted butter and place it back under the broiler for 1 - 2 minutes, rotating the sheet pan half way through, until the surface starts to turn a golden brown in color. DO NOT WALK AWAY FROM THE PANCAKES while they are under the broiler, as they can burn quickly!
Remove the sheet pan pancakes from the oven as soon as they turn golden brown.
Cut the pancakes (while they are hot) into 8 (large), or 12 (medium), or 16 (small) portions.