In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt until evenly combined.
In a separate bowl, whisk together the whole milk, egg, melted butter, and vanilla extract. Pour the wet ingredients into the dry ingredients and stir gently until just combined — a few small lumps are perfectly fine and actually preferred.
Let the batter rest for 5 minutes so the baking powder activates and the flour hydrates. This gives you the fluffiest result.
Generously grease two small round oven-safe pans or ramekins (4 to 6 inches) that fit inside your air fryer with melted butter or nonstick cooking spray. Pour about 1/3 cup of batter into each pan.
Place the pans in the air fryer basket. Air fry at 330°F for 7 to 8 minutes until the tops are set and lightly golden and a toothpick inserted in the center comes out clean. The pancakes will puff up beautifully — they come out thick and fluffy, almost like a cross between a pancake and a cake.
Carefully remove the pans and gently flip the pancakes out onto a plate. Grease the pans again and repeat with the remaining batter.
Stack the warm pancakes, top with a pat of butter and a generous drizzle of maple syrup, and add fresh berries if desired. Serve immediately while they are warm and fluffy.