Start with the glaze: Melt the butter in a small saucepan over medium-high heat. Let it foam and turn golden brown—watch for those nutty aromas and brown specks. Remove from heat and cool slightly.
Combine the powdered sugar, vanilla, and brown butter in a small bowl. Whisk until smooth. If the glaze is too thin, add more powdered sugar until it’s just right. Set aside.
Preheat your air fryer to 400°F. Let the basket heat up for about 3-4 minutes.
In a medium bowl, whisk together flour, sugar, baking powder, salt, and cinnamon. Make a well in the center and add milk, vanilla, lemon juice, and eggs. Stir until combined, then fold in the diced apples.
Line your air fryer basket with parchment paper and lightly spritz it with oil. Drop ¼ cup-sized dollops of batter into the basket, spacing them apart.
Spray or brush the tops of the fritters with a light coat of oil. Air fry at 400°F for 4-5 minutes or until golden brown. Flip and cook for another 4-5 minutes.
Transfer the fritters to a cooling rack and drizzle generously with brown butter glaze while still warm. Serve immediately and enjoy!
