1. Preheat your Air Fryer to 360 F (180 C). Grease a round baking dish. Then, line with baking paper (baking dish must fit into the Air Fryer basket).
2. Place the two whole oranges in a saucepan and cover them with enough water. Bring to the boil. Lower the heat to a simmer. Cook, covered, for 1 hour, making sure that the oranges remain submerged with water. Drain and let cool.
3. Cut the oranges into quarters, remove the seeds if any. Then, place into a blender and process until smooth.
4. Beat the eggs with sugar until dissolved, then add the orange puree, agave nectar, ground almonds, flour, and baking powder. Mix well.
5. Pour into prepared baking dish. Cook in the Air Fryer for 40-45 minutes or until tested done. Leave the cake in the pan to firm up, about 10 minutes.
6. Remove the baking paper and turn over in wire rack to finish cooling.
7. To serve, dust with icing sugar on top. Decorate with orange slices and almonds.