In a medium size saucepan heat some olive oil and add the onion and garlic until softened. Add the cherry tomatoes, the vegetable stock, chili flakes and some salt and pepper and simmer for about 10-12 minutes until the tomatoes start to release their juices. When most of the liquid has evaporated, lower the heat and add the butter and herbs. Stir to create a thick creamy mixture.
Meanwhile, cook the pasta in plenty of salted boiling water following pack instructions. Keep 1 cup of the pasta water. When the pasta is cooked, drain and add to the sauce. Add ½ cup parmesan and some of the pasta water if you would like a silkier sauce. Cook for 1 one minute. Serve in plates and sprinkle with the remaining parmesan.