In a large bowl combine egg, salt and milk. In another bowl combine flour and baking powder, making sure to mix them. Add flour mixture into the egg bowl. Mix to fully combine.
Separate the dough into 2 balls, roll the dough out to about 1/4 inch thick, and let sit for 20 minutes. Tip: When rolling out the dough, roll on floured wax paper for easy cleanup!
Using a knife, pizza cutter or sharp scissors, cut into strips. Spread strips out, dust with a little flour on top and let sit for 10 minutes. Note about noodle size: the noodles will double in size once cooked so thinner is better (unless you want chunky noodles).
When ready to use, bring soup to a low simmer and add noodles, cooking for 8-10 minutes.