1Prepare the filling: in a bowl, mix drained tuna with mashed potato, beaten egg, chopped capers, and parsley. Season with salt and pepper.
2Cut brick sheets in half (for half-moons) or leave whole for larger triangles.
3Place a spoonful of filling at one end of the sheet and fold into a triangle, pressing edges to seal.
4For a secure seal, brush edges with a little water or egg white.
5Lightly brush bricks with olive oil using a pastry brush.
6Preheat air fryer to 190°C (375°F) for 3 minutes.
7Arrange bricks in the air fryer basket without overlapping.
8Cook for 8-10 minutes at 190°C (375°F), turning gently halfway through (after about 5 minutes).
9Serve warm with lemon wedges and a green salad.