Make the batter: In a large bowl, whisk together sifted flour, baking powder, salt, and sugar.
Add the milk, egg, and melted butter to the dry ingredients and stir until just combined (don’t overmix).
Make the cinnamon swirl: In a small bowl, combine brown sugar and cinnamon.
Cook the pancakes: Heat a non-stick skillet over medium heat. Pour 1/4 cup of pancake batter onto the skillet.
Swirl the cinnamon mixture on top of the pancake batter, then use a toothpick or knife to create a swirl pattern.
Cook until bubbles form on the surface, then flip and cook for another 1–2 minutes until golden brown.
Repeat with remaining batter.