Preheat and lightly grease a large skillet or electric griddle.
Mix the flour, salt, and baking soda together in a bowl. Add the egg, buttermilk, and butter; stir together lightly, but keep it lumpy. The batter should look thick, spongy, and puffy.
Drop 1/3 cup of the batter onto the cooking surface, spreading lightly with the bottom of the cup. Cook until lightly-browned on each side, 1 to 2 minutes per side.