In a medium-sized mixing bowl, whisk together the flour, sugar, baking soda, and salt until well combined.
In a separate mixing bowl, whisk together the milk, egg, and melted butter until well combined. If you're using any optional flavorings, add them now.
Add the wet ingredients to the dry ingredients and whisk until just combined. Don't overmix the batter, as this can result in tough pancakes.
Let the batter rest for about 5-10 minutes. This allows the gluten in the flour to relax, resulting in more tender and fluffy pancakes.
While the batter is resting, preheat a non-stick skillet over medium heat. You can also use a griddle if you have one.
Grease the skillet with cooking spray, butter, or oil. You only need a small amount, as you don't want the pancakes to be greasy.
Using a 1/4 cup measuring cup, ladle the batter onto the skillet. You can make the pancakes as big or as small as you like, depending on your preference.
Cook the pancakes for 2-3 minutes on one side, or until bubbles start to form on the surface. Flip the pancakes and cook for an additional 1-2 minutes on the other side, or until golden brown.