In a medium mixing bowl, whisk together the flour, sugar, and baking powder.
½ cup all purpose flour, 1/3 cup granulated sugar, ½ teaspoon baking powder
Stir the melted butter into the flour mixture. It should have a similar consistency to cookie dough.
4 Tablespoons salted butter, melted
In a separate bowl, combine the blueberries, brown sugar, cornstarch, vanilla, and cinnamon.
2-3 cups frozen or fresh blueberries, 2 Tablespoons brown sugar*, ½ teaspoon cornstarch, ¼ teaspoon vanilla, 1/8 teaspoon cinnamon
Pour the blueberry mixture into a lightly greased 7-inch baking dish or air fryer cake barrel. (Alternative: Use 4 7-ounce ramekins.)
Crumble the topping over the blueberries.
Air fry at 310 degrees for about 30-35 minutes or until heated through and golden. (For 7-ounce ramekins, air fryer for 19-21 minutes at 320 degrees.) Check the cobbler after 10-12 minutes and cover it with foil so the top does not brown too much.