Tip the miso paste, Sherry or sake,
sugar and garlic into a sealable food bag.
Season with a generous grinding of black
pepper, then squash it all together until
completely mixed. Add the steak, gently
massage the marinade into the steak
until completely coated, then seal the
bag. Pop the bag into the fridge and leave
for at least 1 hr, but up to 2 days is fine.
To cook, heat a heavy-based frying pan,
griddle pan or barbecue until very hot.
Wipe the excess marinade off the steak,
then sear for 3 mins on each side for
medium-rare or a few mins longer if you
prefer the meat more cooked. Set aside
for 1 min to rest. Carve the beef into
thick slices and serve with a crunchy
salad made with the spinach, cucumber,
celery, radish and sesame seeds.