Prepare the Noodles and Sauce: Cook the udon noodles according to the package instructions. This usually involves boiling them for just 1-2 minutes until they separate and are heated through. Drain immediately in a colander and rinse with cold water to stop the cooking process. Set aside. In a small bowl or jug, whisk together the soy sauce, mirin, oyster sauce, and sugar. Set this aside too.

Sauté the Aromatics: Heat the oil in a large frying pan or wok over a medium-high heat. Once it’s shimmering, add the sliced onion and stir-fry for 2-3 minutes until it starts to soften. Add the minced garlic and grated ginger and cook for another minute until fragrant.

Cook the Prawns: Add the peeled king prawns to the pan. Cook for 2-3 minutes, stirring frequently, until they turn pink and are just cooked through. Be careful not to overcook them. Remove the prawns from the pan and set them aside on a plate.

Stir-fry the Vegetables: Add the sliced carrots and shiitake mushrooms to the same pan. Stir-fry for 4-5 minutes until the carrots are crisp-tender and the mushrooms have softened and taken on a little colour.

Add the Greens: Add the bok choy leaves to the pan and cook for 1-2 minutes, just until they have wilted but still retain a bit of crunch.

Combine Everything: Return the cooked prawns to the pan along with the drained udon noodles. Pour the prepared sauce all over the noodles and vegetables.

Toss and Serve: Using tongs, gently toss everything together for 1-2 minutes, ensuring the noodles and all the ingredients are thoroughly coated in the glossy sauce and heated through. What works best for me is to lift and turn the noodles from the bottom to avoid breaking them.

Garnish and Enjoy: Divide the yaki udon noodles among four bowls. Garnish generously with sliced spring onions, toasted sesame seeds, and a sprinkle of bonito flakes if you're using them. Serve immediately.