Pasta Pomodoro

Ingredients

• ¼ cup olive oil
• 1 medium onion chopped
• 4 garlic cloves minced
• 1/4 tsp crushed red pepper flakes
• 1 28- ounce Can whole peeled tomatoes puréed in a food processor or blender
• 1/2 tsp salt or as per taste
• 1/4 cup chopped basil
• 1lb spaghetti
• 2 Tbs. unsalted butter cut into pieces
• ¼ cup finely grated Parmesan cheese
• Extra basil and Parmesan for garnish