1. Preheat the oven to 200C/400F/gas mark 6. Cut 7.5cm/3in circles out of the pastry and line 16 patty tins. Reserve the remaining pastry to make the lattice tops.
2. Bring a large pan of water to the boil and cook the cabbage leaves for 30 seconds. Remove the leaves with a slotted spoon and refresh them in a bowl of cold water. Drain thoroughly and dry well on a clean tea towel. Roll the cabbage leaves and shred finely.
3. Soften the soft cheese in a bowl and blend in the fromage frais. Stir in the tuna, prawns, tomato and lemon zest and season well to taste. Divide the mixture among the 16 pastry cases and top with the cabbage.
4. Brush the edges of the pastry cases with milk. Cut 3mm-5mm wide strips from the remaining pastry and lay two strips across the patties one way, pressing them firmly on to the edges to attach them. Brush with milk and lay two strips over them at right angles to make a lattice effect, attaching them in the same way. Cook towards the centre of the oven for 15-25 minutes until the pastry looks crisp and golden. Allow the pies to cool, then remove from the tins.