Heat oven to 200C/180C fan/gas 6. Unroll the pastry and cut into 24 squares. Divide the lentils and feta between the pastry squares, leaving a border around the edge. Beat the egg and brush a little of it onto the edges of the pastry, then pinch together to seal in a cross shape at the top. Transfer the pastries to a large baking sheet, brush with the remaining beaten egg and bake for 20 mins until golden. Serve as a starter with dressed leaves.