A staple in Japanese cooking, miso is a fermented soybean paste that adds delicious depth of flavour to everything it encounters. It's so versatile, it's even used in desserts! Here, we've mixed it with butter to bring a hit of rich umami to this light and satisfying beef noodle bowl that's ready in a matter of minutes.
Bring a saucepan of water to the boil for cooking the noodles. Place butter and miso in a bowl and give it a good stir to combine. Peel and grate ginger and garlic, add to miso butter and stir to combine. Set aside at room temperature. Rub steak with oil and season with salt.
Heat a frypan over high heat. Add steaks and cook for 4 minutes each side. Add ½ the miso butter to pan and cook steak for a further 30 seconds on each side, basting with the butter. If you prefer your steak medium, cook for a further 1 minute each side. Transfer to a plate and pour over miso butter. Set aside to rest. Wipe out pan and allow to cool slightly. While beef is resting, continue with step 3.
Roughly chop broccolini into small pieces and thinly slice spring onions, keeping the white and green parts separate. Add remaining miso butter to the same pan you used for the beef and place over medium heat. Add broccolini and white part of spring onion and cook for 2–3 minutes or until broccolini is almost tender.
Juice ½ the lemon and cut remaining lemon into wedges. Add lemon juice and soy sauce to pan, stir to combine and remove from heat.
Meanwhile, cook noodles in a saucepan of boiling water for 3 minutes. Drain.
Thinly slice steak. Toss noodles with broccolini mixture and any resting juices from steak. Divide noodles between bowls, top with steak and green spring onion. Serve with lemon wedges.