Preheat the air fryer to 350°F (175°C).
Using the back of a spoon, press down the center of each bread slice to create a rectangular well, leaving a 1/2-inch border.
In a small mixing bowl, whisk together the Greek yogurt, egg, maple syrup, and vanilla extract until the mixture is completely smooth.
Divide the yogurt custard evenly between the two bread wells.
Place fresh berries on top of the custard and sprinkle lightly with cinnamon.
Carefully place the slices into the air fryer basket in a single layer.
Cook for 8 to 10 minutes, or until the custard is set and the edges of the bread are toasted.
Remove and allow to cool for 2 minutes to let the custard firm up before serving.