Melt butter in a sauce pot over medium heat. Add Onion (diced) and garlic (minced) and chopped parsley. Cook to translucent. Add red pepper flakes and vodka. Reduce heat and simmer for 2 minutes. Add tomatoes with juice. Increase heat to high, while breaking up tomatoes with a spoon. Cook for about 5 Minutes. Stir in heavy cream and salt. Cook until sauce begins to thicken (approximately 5 minutes ) Toss with cooked Pena and sprinkle with Grated Parmesan Cheese and Serve.