In a large bowl put in the egg, butter, sugar, vanilla extract (optional) and hand whisk together.
Add flour and milk, continue mixing until mixture is smooth.

Heat a lightly oiled frying pan over medium heat and pour/scoop in the mixture to your preference on desired pancake size.
1/2 of mixture will make 2 very large pancakes, 1/4 of mixture will make 4 'normal' sized pancakes.

When the pancake starts to show little bubbles ontop (1-2 minutes cooking), flip and cook other side.