In a medium mixing bowl, whisk together the flour, sugar, baking powder, and salt until well combined. This helps the leavening distribute evenly, so all the pancakes rise the same way. In a separate bowl or large measuring cup, mix the milk, egg, melted butter, and vanilla. (Tip: Let the butter cool slightly before mixing to avoid warming the egg too much.)
Pour the wet mixture into the dry ingredients and gently stir until the batter just comes together. A few lumps are fine, overmixing can make the pancakes dense instead of fluffy.
Heat a skillet or griddle over medium heat and lightly butter or use nonstick spray on the surface. I like to test the heat with a tiny drop of batter first. When it sizzles gently, it’s ready.
Scoop 1/4 cup of batter per pancake onto the skillet. Let them cook until bubbles appear on the surface and the edges look slightly set, about 2 to 3 minutes. Flip and cook the other side for another 1 to 2 minutes until golden brown.
Serve warm with your favorite toppings. If you have leftovers, layer them with parchment and freeze in a zip-top bag. They reheat well in the toaster or microwave for busy mornings.