Trim the individual broccoli stalks from the main stem, discard the stem and check that about 220 g (7 oz) of broccoli remains. Wash thoroughly and drain, then trim and slice the stalks very thinly, reserving the flower heads.
Melt the butter in a medium pan, add the sliced stalks, cover with greaseproof paper and a lid. Cook very gently for 10 minutes until tende