Prepare your pizza dough either by placing the yeast, flour, semolina, salt, sugar and water in your bread machine in the manufacturer's recommended order and selecting the dough or pizza dough cycle. Alternatively, combine all the ingredients except for the water, make a well in the centre, add the water and stir with a wooden spoon until well combined. Turn out onto a floured surface and knead for 10 minutes. Transfer to a lightly oiled bowl, cover in cling film and leave to rise until doubled in size, about one hour.
Meanwhile, prepare the pizza sauce.
Add half the olive oil to a small saucepan along with the garlic and seaweed, if using. Cook over a medium-high heat for one minute.
Add the tin of chopped tomatoes and cook for a further 15-20 minutes until it is thick and reduced.
Taste test and if it's too acidic add caster sugar to taste - start with one teaspoon. Season to taste with salt and pepper, stir in the remaining olive oil and set aside.
Preheat your oven to 240C/220C (fan)/475F. Sprinkle two large baking trays with coarse polenta.
Divide the pizza dough into two and roll out onto the baking trays. Leave to prove for a further ten minutes.
Divide the pizza sauce between the two pizzas and arrange your toppings.
Bake for 12-14 minutes, until the cheese is golden and bubbly.