In a food processor, combine the flour and semolina and pulse several times. In a measuring cup, mix the whole eggs and egg yolks. With the machine on, pour in the eggs and process until the flour is moistened; the dough may still be a bit crumbly. Turn the dough out onto a floured work surface and knead until silky smooth, about 3 minutes. Wrap in plastic and let stand at room temperature for 30 minutes.
Divide the dough into 3 pieces; keep 2 pieces wrapped. Flatten the remaining piece of dough, dust it with flour and roll it through a hand-cranked pasta machine, beginning at the widest setting and stopping at (or just before) the thinnest; dust the dough lightly with flour between settings. Cut the strip into 4 pieces, 10 to 12 inches each, and dust with flour. Roll up each piece loosely and slice 3/4 inch thick. Uncoil the pappardelle and toss them with flour. Transfer the pappardelle to a flour-dusted baking sheet. Repeat with the remaining pieces of pasta. Toss the pappardelle occasionally to dry them out evenly and keep them from clumping.