How do you cook marrow ?
I assume we're talking about beef or veal bone marrow but possibly you are using the UK term for a summer squash. Marrow bones can be roasted in the oven and served with a persillade (parsely and garlic) and it's great if you have the little marrow spoons too in order to scoop out the delicious goo.
If it's summer squash, then stuffed with some good strong flavours is the best way to go.... They're pretty bland, IMO better picked as a courgette and eaten that way! However, either slice your marrow in half, or if it's a really big one, slice into rounds, take out the seeds, and fill with anything you like.... Ground meat or a breadcrumb base, with small cut veggies, just make sure you put p,entry of flavour in! I quite like a lamby moroccan affair in the middle, then shove it in the oven. But seriously, pick them before they become marrows! If you have a lot of marrow, then I heartily recommend marrow and ginger jam - the marrow acts as a fairly bland bulk so the jam/preserve has a great ginger kick!