Remove the pistils from the courgette flowers and rinse delicately. Clean the parsley and once rinsed chop it finely with the onion and the courgette flowers. Heat the oil in a pan, add the chopped mix and the diluted saffron then season with salt and pepper.Simmer for 15 over a low heat, mixing from time to time with a wooden spoon. Whiz the mixture and put it back into the pan. Add the broth and simmer for a few more minutes, stirring well.Whisk the yolk and the pecorino in a bowl. Remove the pan from the heat and add the egg mix, stirring constantly. Cook the vermicelli in plenty of boiling salted water, place them in a serving dish and pour the sauce over it with a sprinkle of parsley, mix well and serve.