In a medium bowl, whisk together the milk, eggs, sugar, and salt.
Stir in half of the flour into the milk and egg mixture and stir until combined. Then add the remaining flour and melted butter, mixing until smooth.
Preheat a 10-inch nonstick skillet over medium heat. Generously grease the skillet with nonstick cooking spray or coat with butter.
Using a ⅓ cup measure, remove skillet from the heat, pour the batter into the hot skillet and with one hand and with the other, swirl the pan to evenly distribute the batter. Return skillet to the heat and cook until set; about 1 minute. With a spatula, flip and cook on the other side for about 30 seconds, or until lightly golden.
Remove the pancake from the pan onto a plate. Repeat with remaining batter. Roll or fold the pancakes and serve with jam.