Pour cornmeal into a large bowl; cover with boiling water. Let stand until slightly softened, about 5 minutes. Stir in flour, sugar, melted butter, baking powder, and salt. Mix in milk and egg until batter is smooth.
Heat a lightly greased griddle over medium heat. Drop spoonfuls of batter onto the griddle and cook until edges are dry, 2 to 3 minutes. Flip and cook until browned on the other side, 2 to 3 minutes more. Repeat with remaining batter.