Divide the courgettes from the flowers, rinse them then dry delicately with a tea towel and chop them into slices. Trim, rinse and dry the courgettes, then chop them à la julienne. Peel the shallot and the onion, once dried chop them finely. Heat the oil in a saucepan, add the shallot and the onion and fry until soft but not golden.Add the courgettes and brown for a few minutes, mixing from time to time with a wooden spoon. Sprinkle with 2 spoonfuls of water, cover the pan and simmer for 6-7 minutes over a medium heat. Add the courgette flowers and brown them for a minute.Melt the saffron with a spoonful of water and simmer for 5 minutes over a medium heat. Season with a pinch of salt and a grind of pepper. In the meanwhile bring to the boil a pan of salted water, toss the pasta in it and cook al dente, drain it and mix it with the sauce, serve warm.