To prepare the broth, heat a large stainless steel saucepan over medium-high heat, then add the star anise, coriander seeds and cinnamon sticks. Dry toast the spices, tossing occasionally for about 4 minutes, or until fragrant.

Once toasted, remove the spices to a small bowl and set aside. Return the pan to high heat. Add the onion (cut-side down) and sliced ginger, then cook for 5 minutes, or until charred and blackened.

Add the water to the pan along with the toasted spices and beef broth powder, then bring to the boil. Reduce the heat to low and gently simmer for 20 minutes or until fragrant.

Meanwhile, combine the gelatine with 2 tablespoons of cold water. Mix well, then set aside to allow the mixture to bloom.

To prepare the rice noodles, place the noodles in a large microwave-safe bowl with ¼ cup of water, then microwave on high for 3 minutes to lightly steam the noodles. Loosen the noodles gently with tongs, then divide between serving bowls and top with the beef hot pot rolls.

Once the broth has simmered for 20 minutes, strain with a fine mesh strainer into a large, heat-proof bowl, then return the strained broth back into the saucepan.

Place over high heat then add the bok choy (if using) and cook for 1 minute, or until bright green. Place the cooked bok choy with tongs directly onto the hot noodles, next to the beef.

Bring the broth to the boil, then reduce the heat to low. Stir through the bloomed gelatine, until just melted. Season the broth with sugar (if using) and fish sauce to taste.

Ladle the hot broth over the hot pot rolls and the noodles, then top with bean sprouts, sliced brown onion and herbs. Serve with lemon cheeks on the side.