Cook the rice in a pan of boiling water according to pack instructions. Drain and set aside.
Meanwhile, preheat the oven to 190°C, fan 170°C, gas 5. Grease with butter and line a 20cm x 30cm Swiss roll tin with baking parchment.
Melt 50g butter in a pan over a medium heat, add the onion and pepper and sauté until tender.
Drain the tuna into a large bowl, reserving 100ml of the brine. Add the cooked onion, pepper and rice to the bowl along with the curry powder and 2 tablespoons of the parsley. Mix until well combined. Press into the prepared tin and top with the cheese.
Whisk the reserved brine with the milk and eggs until combined. Pour over the tuna mixture and bake for 50 minutes
Cut into 16 squares then cut each square into 2 triangles. Serve garnished with the remaining parsley, some halved cherry tomatoes and a few rocket leaves.
Cook’s tip: this recipe makes great little snacks to take on picnics or to serve as canapés, but it also makes a tasty summer supper. Cut into larger pieces and serve with salad.