In a large bowl, whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt until well combined.
1 ½ cups all-purpose flour, 1 cup granulated sugar, ½ cup cocoa powder, 1 teaspoon baking powder, ½ teaspoon baking soda, ¼ teaspoon salt
In a separate bowl, beat the butter, eggs, milk, and vanilla extract until smooth and creamy.
½ cup unsalted butter, 2 large eggs, 1 teaspoon vanilla extract, ½ cup milk
Gradually add the dry ingredients to the wet mixture, alternating with water, and mix gently until just combined. Avoid overmixing.
¼ cup water
Fill each cupcake mold about two-thirds full with batter. Place them in the air fryer basket, leaving space between each for air circulation.
Air fry at 300°F (150°C) for 10–12 minutes, or until a toothpick inserted in the center comes out clean. Let the cupcakes cool completely before decorating as directed above.