It's imperative to get the frying pan hot enough but not too hot. If the pan is not hot enough the pancakes will soak up the fat in the pan and end up greasy. But if the pan is too hot then the butter will burn and the batter won't spread far enough as it will cook too quickly. I generally find a medium-hot heat adequate. For example, if my hob heat went from a scale of 1 (low) to 9 (high) then I would go for around 6 - in other words, just ahead of the midway heat. Test that the pan is hot enough to begin cooking by dropping a small knob of butter into the centre - it should immediately sizzle. if the pan/ butter is smoking then it is too hot.