Add the baking soda to a saucepan and fry for about 15 minutes on low heat or spread the soda over a baking tray lined with parchment paper and bake for 1 hour at 120°C (250°F).
In a bowl combine baked soda, all purpose flour, lukewarm water and an egg. Knead well. You may use a dough hook attachment on your electric mixer or your hands to make the noodle dough. Knead for 15 minutes by hand or 5 minutes with an electric mixer.
roll out the dough
Roll out the dough to 2cm (0.8 inch) thickness. Wrap the dough in plastic foil and let it rest in a fridge for at least 30 minutes.
Divide the dough into four portions. Roll each portion out using a pasta machine. Progress through the thickness settings one by one until you reach thickness nb. 4 (out of 6). If you are hand rolling them make sure they are rolled out to 1 - 2 mm or 1/16 inches. Cut into desired lengths and shapes. Dust the noodles with rice flour and keep them, shake off the flour and roll into a nest.
You can cook fresh noodles right away in a pot filled with boiling salted water for 40 - 60 seconds. Or you can store them for up to 2 months. If you want to dry your homemade noodles for future use, spread the nests on a large baking sheet. Cover with a kitchen towel and dry for about 3 - 5 days, turning it a few times.