Preheat the air fryer to 160°C for 5 minutes. Lightly grease a shallow cake tin or silicone mould that fits inside the air fryer basket.
In a mixing bowl, whisk together the eggs, sugar (or date syrup), oil and vanilla extract until well combined.
Stir in the ground almonds, baking powder and cinnamon to form a smooth batter.
Spoon the mixture into the prepared tin or mould and smooth the surface with a spatula. Press the pitted cherries into the batter and scatter over the sliced almonds, if using.
Place the tin carefully into the air fryer basket and cook at 160°C for 25–30 minutes, or until golden and set.
Test the centre with a skewer or cocktail stick. If it comes out clean, the squares are ready.
Leave to cool in the tin for 10 minutes before transferring to a wire rack to cool completely.
Cut into squares, placing a cherry in the centre of each piece where possible, or simply remove the squares from the silicone mould.