Preheat the air fryer to 175°C. Spray a 6-cup muffin tin
with cooking spray.
In a mixing bowl, combine the sweetener, almond flour,
baking powder, cocoa powder, baking soda, cinnamon, nutmeg, and salt and stir
until well blended.
In another mixing bowl, mix together the milk, butter, egg,
and rum extract until thoroughly combined. Slowly and carefully pour this
mixture into the bowl of dry mixture. Stir in the blueberries.
Spoon the batter into the greased muffin cups, filling each
about three-quarters full.
Bake for 15 minutes, or until the center is springy and a
toothpick inserted in the middle comes out clean.
Remove from the basket and place on a wire rack to cool.
Serve immediately.
