Preheat oven to 250°F. Line a baking sheet with aluminum foil for easy cleanup.

Spread baking soda on lined baking sheet. Bake for 60 minutes. Remove from oven.

Place hot water in a medium bowl. Sprinkle 2 teaspoons of baking soda over the surface and stir until dissolved. Add cool water and stir.

Add flour and stir until a dough forms. Turn out onto a clean work surface and knead for 5 minutes. Wrap in plastic and let rest for 20 minutes. Knead for another 5 minutes, re-wrap, and refrigerate for 1 hour.

Divide dough into four pieces and roll through a pasta machine to desired thickness. Cut pasta using the spaghetti cutter and let dry for 20-30 minutes.

Bring a large kettle of salted water to a boil. Add noodles and cook 2-3 minutes or until tender but still chewy.

Serve in warmed bowls covered in a broth soup.