In a small bowl, mix the 2 cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon ground cinnamon, 3 tablespoons brown sugar, and1/2 teaspoon kosher salt.
Add the 1 large egg yolk, melted 2 tablespoons butter, 1 teaspoon vanilla extract, and 3 tablespoons heavy cream, and mix well.
Add in the diced 1/2 cup apples, and mix well.
Spray your ramekins or another air fryer safe (remember air fryer safe is generally oven safe) with olive oil spray. Scoop your batter into the greased ramekin.
Then make your topping in a small bowl, and mix the 4 tablespoons flour, 4 tablespoons brown sugar, 1 teaspoon ground cinnamon, and 3 tablespoons butter. Sprinkle on top. Then set the ramekins into the air fryer for 12-14 minutes at 320 degrees F, air fryer setting.