Delicious Pizza

This is a recipe from Food and Drink 2014, except that it is supposed to be grilled and in 4 pizzas and I baked it on a stone in my oven as one large pizza.  The Sauce is what I really enjoyed about this pizza, and it was so easy to make.

3 tbsp olive oil
1 small onion, finely shopped
 Kosher salt and freshly ground black pepper
1 clove garlic, minced
1/4 tsp red chili flakes
1 can (798 ml) San Marzano Tomatoes (or the best quality you can find)
1/2 tsp granulated sugar
375 g Hot Italian sausages
1 pkg (680g) Pizza Dough
1 cup pitted black olives
125 g drained fior di latte, torn into small pieces (or the best quality mozzarella you can find, grated)
1/4 cup finely shredded fresh basil leaves

1. In a medium saucepan, heat 1 tbsp of the oil over medium heat.  Add onion and salt and pepper to taste.  Cook, stirring often, until onion is softened but not browned, about 5 minutes.  Add garlic and red chili flakes and cook, stirring until fragrant but not browned, about 30 seconds.
2. Add tomatoes and sugar.  Bring to a boil, breaking up tomatoes with the back of a spoon.  Reduce heat to medium-low and simmer, uncovered and stirring occasionally, until sauce has thickened and reduced, abut 50 minutes.  Stir more frequently and reduce heat, if necessary, toward end of cooking time so sauce doesn't scorch.  Taste and add more slat and pepper if necessary.  Remove from heat and let cool to room temperature.
3. Meanwhile, heat a small nonstick skillet over medium.  Remove casings from sausages and crumble meat into skillet.  Cook, stirring often, until sausage meat is completely cooked and no longer pink, 8 to 10 minutes.
4. 30 minutes before cooking remove dough from fridge.
5. Heat oven to 400F.  
6. Roll dough out on lightly floured surface to size of pizza stone and place on stone.
7. Spread tomato sauce over crusts.  Sprinkle with cooked sausage, black olives and cheese.
8. Bake for approximately 25 minutes or until crust is cooked through.