Using a half-cup measure, pour a pancake in the middle of the preheated pan. The half-cup measure will make a pancake about six inches in diameter. Cook until the top starts to look a little stiff, and bubbles start to form in the batter. Then slip a spatula under it and flip it over. If it won't flip without tearing, you didn't cook it long enough. On the other hand, if it is stiff as a board, you waited too long. After flipping, cook until the pancake has stopped rising, has firmed up, and no longer looks wet around the edges. Remove it from the pan and transfer it to the cookie sheet in the oven to keep it warm while you cook the others.