Make the sauce – Combine the sauce ingredients in a small bowl and set aside. 

Cook the onion and garlic – Heat the olive oil in a large, heavy-based frying pan over medium–high heat. Add the onion and garlic and cook, stirring, for 30 seconds until fragrant. 

Add the beef – Add the beef and cook, stirring, for 3–4 minutes until browned, breaking it up with a wooden spoon or spatula as you go. 

Add the sauce – Add the sauce and cook for 1–2 minutes, stirring, until caramelised.

Add the veggies – Add the broccoli, then place the lid on and cook for 1–2 minutes. 

Add the noodles – Push the beef and broccoli mixture to the outside of the pan to make a well in the middle. 

Pour in 1½ cups (375 ml) of the water and add the uncooked noodles to the centre of the pan. Cook, covered, without stirring, for 1 minute. Flip the noodles and cook for another 1 minute, covered, or until the noodles are just pliable. 

Using tongs, toss the noodles through the beef and broccoli. 

Thicken the sauce – In a small bowl, combine the cornflour with the remaining ¼ cup (60 ml) of water. 

Add the cornflour and water mixture to the stir-fry, stir it through, then cook, tossing with tongs, for 1–2 minutes or until the sauce has thickened and created a lovely glaze around the noodles. 

Season to taste with the tamari or soy sauce.

Serve – Serve scattered with sesame seeds and sliced spring onion. Drizzle with chilli oil, if using.