Preheat your oven to 190°C (375°F), or 170°C for fan ovens, or gas mark 5. Always refer to the pizza base packaging for any specific baking instructions.

Drain some of the liquid from the chopped tomatoes and pour them into a saucepan along with the tomato purée and dried mixed herbs. If using whole plum tomatoes, break them up gently in the pan using a spoon. Allow the sauce to simmer over low heat until it thickens slightly and becomes rich in flavor.

Meanwhile, prepare the toppings. Drain the tuna and flake it gently with a fork to break it into bite-sized pieces. Peel and finely slice the red onions. Grate the mature cheddar and set it aside.

Spoon the tomato sauce evenly over both pizza bases, spreading it to the edges with the back of a spoon. Distribute the tuna, sweetcorn, and red onions over the sauce, arranging them evenly for full coverage.

Sprinkle a light layer of grated cheddar cheese over the toppings. You’re not aiming to smother the pizza—just enough to bind the toppings and add a golden finish.

Place the pizzas on the middle rack of the preheated oven and bake for 15 to 20 minutes, or until the edges are crisp and the cheese has melted and turned lightly golden. Serve warm straight from the oven.