Prepare noodles by following instructions on the packet. Bring a pot of water to a rapid boil. Drop fresh noodles carefully into the boiling water. Allow to cook for 3-4 minutes. Remove from heat. Drain hot water. Rinse noodles with cold water a couple of times till the water is no longer hot and the noodles have cooled down. Add enough cold water to just submerge the cooked noodles. Set aside until ready to use.
Have your peeled prawns at the ready. If using frozen prawns, submerge prawns in hot water for 15-20 seconds till they just start to soften. Drain water completely. Squeeze the frozen prawns and drain the liquid completely. Set aside.
Prepare noodle sauce by mixing tomato paste, soy sauce, miso paste, cooking sake and pepper in a small bowl.
Heat a medium wok on high. Add butter and garlic. Stir-fry for a few seconds until aromatic. Add prawn and spring onions. Stir-fry for a minute until prawns start turning red and are no longer translucent.
Drain noodles completely and add to the wok.
Add the prepared sauce and mix everything well using a flat spatula or tongs. Stir-fry for 2-3 minutes until the noodles are hot and everything is well combined.
Remove from heat. Serve hot or allow to cool to room temperature before packing away in lidded glass container. Will keep in the fridge for up to 2 days.