How to Make It
Place flour and a pinch of salt in bowl of a food processor. Turn machine on, and with the blade running, slowly pour in egg yolks. Process until ingredients come together, about 1 minute.
Remove dough from food processor. Transfer to a well-floured work surface, and knead until dough is smooth and springs back when pressed with thumb, about 15 minutes. Wrap dough tightly in plastic wrap, and refrigerate for at least 30 minutes or up to overnight.
Let dough return to room temperature. Cut into 6 pieces. Working with one piece at a time, keeping others covered, pass pasta through a pasta machine set to widest setting. Reduce width to second- widest setting, and run through again. Fold dough in thirds (like a letter), and repeat passing procedure through widest and second-widest settings. Set dough sheet on a floured surface, and dust with more flour. Repeat with remaining pieces.
Let pasta sheets dry until leathery, about 10 minutes. Run one sheet through the spaghetti cutting attachment of pasta machine. (Alternatively, loosely roll sheets from short end to short end, and cut with a knife into 1/8-inch strips.) Shake out excess flour, and place portion on a floured baking sheet; sprinkle with flour. Repeat with remaining sheets.
Uncooked pasta will keep overnight, tented loosely with plastic wrap. To freeze, place baking sheet with individual coils in freezer until solid, about 6 hours, then transfer to a freezer bag. Pasta will keep up to a month in freezer; cook directly from frozen, adding 1 to 2 minutes to cooking time.