Preheat your air fryer to 320°F (160°C). A short preheat helps the bites rise evenly and cook through without over-browning.
Whisk the dry ingredients. In a medium bowl, whisk flour, sugar, baking powder, baking soda, and salt until well combined.
Mix the wet ingredients. In a separate bowl, whisk milk, egg, melted butter (slightly cooled), and vanilla until smooth.
Combine to make the batter. Pour the wet mix into the dry. Stir gently until just combined.
A few small lumps are fine. If the batter seems too thick, add 1–2 tablespoons milk to reach a thick but pourable consistency.
Prep the mold. Lightly grease the silicone heart mold with nonstick spray or melted butter. Place the mold in the air fryer basket before filling to avoid spills.
Fill the hearts. Spoon or pour batter to fill each heart about 2/3 full.
Add a few mix-ins if you like, then lightly press them under the surface so they don’t burn.
Air fry. Cook at 320°F (160°C) for 7–10 minutes. Start checking at 7 minutes. They’re done when the tops spring back and a toothpick comes out clean or with a few moist crumbs.
Rest briefly. Let the pancake bites sit in the mold for 1–2 minutes to set, then gently pop them out.
If your air fryer is small, repeat with remaining batter.
Serve warm. Drizzle with maple syrup, dust with powdered sugar, or top with fruit and yogurt. Enjoy immediately for the best texture.