1. Cook the udon noodles per packet instructions. Drain and set aside.
2. Thinly slice the beef into strips. Mince the garlic and grate the ginger. Thinly slice the red pepper and spring onions.
3. Make the sauce: mix together soy sauce, hoisin sauce, sweet chilli sauce, sesame oil and a splash of water.
4. Heat a splash of oil in a large wok or frying pan over very high heat. Fry the beef strips in batches 2–3 mins until browned. Remove and set aside.
5. In the same pan, fry the red pepper 3–4 mins. Add garlic and ginger, cook 1 min. Return the beef. Pour in the sauce and toss everything together.
6. Add the cooked noodles to the pan and toss to coat in the sauce. Cook 1–2 mins until piping hot. Serve topped with spring onions and sesame seeds.