For the sauce, add olive oil and garlic to a cold pan and heat over medium-high heat. When the garlic starts to sizzle, add the tomato purée, sugar and oregano. Cook for about 30 minutes, stirring occasionally. Season to taste with salt and pepper then set aside to cool. (You can make the sauce up to three days ahead of time and keep in an airtight container in the fridge.)
Preheat oven and pizza stone to 550°F.