In a bowl, combine the blueberries, granulated sugar, lemon zest, and lemon juice. Let the mixture sit for 10 minutes. If using frozen berries, don't thaw them.
In a second bowl, whisk the flour, brown sugar, baking powder, and salt. Stir in the milk, melted butter, and vanilla until smooth.
Pour the blueberry mixture into a greased 7-inch round pan or 6×6-inch baking dish. Pour the batter over the berries and spread it evenly.
Preheat the air fryer to 320°F (160°C). Air fry for 18–22 minutes, adding 3–5 minutes for frozen berries, until the top is golden, the edges are bubbling, and a toothpick in the topping comes out clean.
Let the cobbler cool a few minutes. Serve warm with vanilla ice cream or whipped cream.