make the toasted rye noodles
Meanwhile, in a small nonstick skillet, toast the rye flour over moderately low heat, stirring, until fragrant, about 4 minutes. Using a rubber spatula, scrape the toasted rye flour into the bowl of a standing electric mixer fitted with the dough hook. Add the bread flour and cake flour. In a medium bowl, stir the baked baking soda and salt with the cool water until dissolved. With the mixer at low speed, slowly blend the baking soda solution into the flour in three additions. Mix, scraping down the bowl frequently, until the dough starts to come together. At medium speed, knead the dough until it forms a shaggy ball, about 10 minutes. Cover the bowl with plastic wrap and let stand at room temperature for 30 minutes.