Heat the olive oil in a large saucepan over medium heat.
Add the onions and fry until softened.
Add the garlic and cook for 30 seconds
Stir in the chili flakes, pureed tomatoes, sundried tomatoes, and season with salt and black pepper to taste.
Cook for 15 to 20 minutes until the sauce has thickened
Turn off the heat and pour in the cream.
In the meanwhile, cook the macaroni in a large pot of salted water according to package directions.
Drain the pasta, reserving 1 cup of the pasta cooking liquid
Add the pasta to the pan with the creamy tomato sauce and toss to coat the pasta
Place saucepan over medium heat.
Add the pasta water, a little at a time, until pasta sauce is thick and creamy.
Melt in the butter and half of the cheese
Toss pasta until the cheese and butter are melted.
Remove the pasta from the heat
Top with remaining cheese, bake to crisp up or leave on stove top to melt. Garnish with basil and serve hot.
