• Make the pizza dough first - add the olive oil, yeast and warm water (the water should be around 35C – you can check this with a meat thermometer) to the mixing bowl of a stand mixer (or large bowl, if making the dough by hand), stir then leave it to sit for 5 minutes while you get everything else ready.
• Add the flour, sugar, polenta and salt into the mixing bowl. Gradually mix the liquid with the dry ingredients until fully combined. Knead for 5 minutes, if using a stand mixer, or 10 minutes by hand.
• Transfer the dough to another bowl that has been lightly greased with oil. Cover with lightly greased cling film and put it in a warm place to prove for 1 hour 30 minutes. After 1 hour of proving, preheat the oven to 230C/210C fan/gas 8.
• Meanwhile, make the tomato sauce - heat the olive oil in a medium saucepan, add the sliced garlic and fry on a low heat for 1 minute, taking care that it doesn’t burn. Add the onions and increase the heat to medium. Cook for 5 minutes, stirring occasionally.
• Add the tins of tomatoes, salt, oregano, chilli flakes and sugar. Stir to combine and cook on a simmer for 20 minutes. Set aside until you’re ready to assemble the pizza.

Assemble and bake:

• Remove the proved dough from the bowl and place it onto a floured surface. Roll it out into a circle, 5cm larger than the diameter of a cast-iron skillet (our skillet is 30cm, so the dough is rolled into a 35cm circle).
• Sprinkle some polenta over the surface of the skillet and then using a rolling pin as a guide, place the dough over the skillet. Use your fingers to press the dough into the skillet, making sure it fits tightly inside it. Now fill the pizza – first with the grated mozzarella, then the slices of pepperoni, followed by the tomato sauce and finally sprinkle the top with the grated parmesan. Trim off any excess dough from around the edges with a small sharp knife.
• Bake for 25 to 30 minutes, or until the crust is golden brown and the filling is set. Check after 15 minutes, if it looks like the edges are starting to brown too much, cover the skillet with tin foil for the remaining time. Remove the pizza from the oven and let it rest for 5 minutes before serving.