Pop the water, yeast and sugar in a bowl and leave for 10 mins for the yeast to activate. Add the olive oil, salt and flour and stir to combine. Tip onto a floured surface and knead for 5 mins until the dough is totally smooth. Put in a lightly oiled bowl, cover with cling film and leave somewhere warm to prove for about an hour, or until it has doubled in size.
Heat some oil in a large sauce pan. Add your onions and cook on a medium heat for about 5 mins, until soft. Add the peppers and cook for another 2 mins, before adding your garlic, mince, salt and pepper and turning up the heat. Cook for 5 mins, until your beef is browned and tender. Set aside.
Heat a little oil in a sauce pan and add your garlic and chilli flakes. Cook for 2 mins, until fragrant and the oil has taken on some colour. Add your passata, oregano, salt and pepper and bring to a simmer. Pop on a lid and simmer for 20 mins until thick.
Turn your dough out onto a floured surface and remove 1/5 of it. Roll the larger piece of dough out into a large circle, then place on a large lined baking tray. Roll out your smaller piece of dough into a circle also.
Place a large circle cutter in the middle of your large dough circle and egg wash around it. Lay your smaller circle over the top and press into the middle and around the sides.
Arrange your pizza sauce, cheesesteak mix and mozzarella around the edge of the circle. Put in the oven for 25 mins.
Heat your evaporated milk and hot sauce in a pan. Stir the cornstarch through the cheese and add to pan, whisking until you have a thick smooth sauce.
Pour your cheese sauce into the centre of your pizza and serve immediately, using the sauce to dip the pizza in.