Instructions

1. Place the cake flour, all-purpose flour, cocoa powder, salt and egg yolks in a food processor. Pulse to combine. With the machine running, gradually add the oil, and then 1/3 to 1/2 cup water until the mixture forms a dough (the dough should stick together if pinched between your fingers). If necessary, add additional water, 1 teaspoon at a time, if the dough is too dry.Place the dough on a lightly floured surface. Gather the dough into a ball and knead until smooth, about 5 minutes. Cover with plastic wrap and refrigerate for 30 minutes.
2. Cut the dough into quarters and press flat. Run each piece of pasta dough several times through a pasta-rolling machine, adjusting the setting each time until the pasta is about 1/8 to 1/16 inch thick. Cut the pasta into fettuccine noodles. Coat the cut pasta with cocoa powder to prevent sticking.
3. Bring a large pot of salted water to a boil over high heat.
4. Ddd pasta to the boiling water and cook until tender but firm to the bite, stirring occasionally, 2 to 3 minutes. Drain the pasta.