Whisk together the flour, sugar, and baking soda., In a separate bowl, whisk together the egg, buttermilk, and oil or melted butter until foamy. Add to the flour mixture and mix until blended; leaving a few small lumps is OK., Let the batter rest for about 5 minutes, while your griddle or frying pan heats up. Heat to medium high (375°F to 400°F), until a drop of water dribbled onto the surface bounces across it. Brush lightly with vegetable oil, or spray with non-stick baking spray., For each pancake, drop 1/4 cup of batter onto the hot surface. Flip the pancakes over once bubbles have risen to the surface, and cook the second side until golden brown. Serve hot.