Chilled ramen (hiyashi chuka)

Instructions

1. To make the noodles, you first need to prepare the alkaline solution that gives the noodles their springy texture and lovely colour. If you are using bicarbonate of soda, preheat the oven to 200°C (400°F) and line a tray with baking paper. Spread the bicarbonate of soda onto the tray and bake for 1 hour, stirring every 15 minutes. This converts the bicarbonate of soda into sodium carbonate, an alkaline powder like kansui powder. Whisk the kansui powder or sodium carbonate with 300 ml (10¼ fl oz) water; this is your alkaline solution. Handle the sodium carbonate with caution and as it can burn the skin.
2. Place the flour and salt in a large mixing bowl and slowly trickle in the alkaline solution. Mix by hand until it forms a very stiff dough, adding more water if it is too tough to knead. The dough should be hard but malleable, and shouldn’t crumble.
3. Roll the dough out into a rectangle as best as you can and feed it through the widest setting of a pasta machine. Fold the dough in half and feed it through the machine once more. Reduce the width between the rollers and feed the dough through again. Continue this process until the dough is approximately 3–4 mm (⅛ in) thick. Using a sharp knife or the pasta cutter on the pasta machine, slice the dough into thin noodles and dust liberally with potato starch to prevent it from sticking. Cover with plastic wrap and transfer to the refrigerator until you are ready to cook the noodles.
4. To make the sauce, whisk all of the ingredients in a bowl until the sugar dissolves. Cover and transfer to the refrigerator to chill (see Note).
5. Heat a non-stick frying pan over medium heat. Pour in the beaten egg, tilting the pan to spread the egg and create a thin omelette. When the omelette is cooked through, remove from the pan, shred and set aside.
6. Using a sharp knife, score a cross into the skin of the tomato. Fill a large bowl with iced water. Bring a large saucepan of water to the boil over high heat. Blanch the tomato in the boiling water for 10 seconds, then transfer to the iced water using a slotted spoon. Peel the tomato by pulling the skin away from the cross. Finely slice the flesh of the tomato, discarding the seeds, and set aside.
7. Blanch the ramen noodles in the boiling water for 1½ minutes, or until cooked, then drain and transfer immediately to the iced water. Once the noodles are cool, drain them well.
8. To serve, place the noodles in a bowl. Arrange the ham, vegetables, kizami nori, wakame and shredded omelette on top, then dress with 60 ml (2 fl oz/¼ cup) of the sauce. Mix everything together before eating, accompanied by a squeeze of fresh lemon.