Blue cheese and tomato pasta

1 pound medium-sized dry pasta shapes 
1 tbsp. olive oil 
1 tbsp. unsalted butter 
½ medium yellow onion, minced 
¼ tsp. crushed red pepper flakes 
1 tbsp. tomato paste 
3 cloves garlic, minced or pressed 
1 (14.5 oz.) can crushed tomatoes 
1 (14.5 oz.) can petite diced tomatoes 
1 tsp. granulated sugar 
1 tbsp. balsamic vinegar 
½ cup heavy cream 
⅓ cup (about 1 ½ oz.) good quality blue cheese, crumbled 
¼ cup freshly grated Parmesan cheese 
1 tsp. dried basil 
Kosher salt and freshly ground black pepper, to taste 

1. Bring a large pot of salted water to a boil and cook the pasta according to the package directions; drain and set aside. 
2. Heat the oil and butter in a very large sauté pan over medium heat. Add the onion and crushed red pepper flakes and cook until the onion is soft and translucent, about 5-7 minutes. 
3. Add the tomato paste and garlic and sauté for 1 minute, until fragrant. Stir in the crushed and diced tomatoes and the teaspoon of sugar. Add the vinegar and bring the mixture to a boil and cook, uncovered, until thickened, about 5 minutes. Add the cream and simmer for 1 minute more. Stir in the cheeses, basil, and cooked pasta. Season with kosher salt and freshly ground black pepper to taste. Serve immediately. 


via : http://www.goodthymesandgoodfood.com