Why ten yolks and not a drop of water
Water dilutes the two things that make an egg ribbon worth the trouble: lecithin and pigment. Ten large yolks weigh about 170 g against 400 g of flour, which puts the dough at 43% hydration — low enough that the sheet stays stiff on the roller and never needs a second dusting.
The lecithin in the yolk also shortens the gluten. That sounds like a defect and is exactly the point: a shortened gluten network rolls thin without springing back, so the ribbon keeps the 6 mm width you cut it to instead of shrinking to 4 mm in the water.
Mixing on the board, then resting
Tip the 00 into a mound, make a well wide enough for your whole hand, and slide the yolks in with the oil and salt. Work the flour in from the inside wall with two fingers, never breaking the outer ring until the last third of the flour has been taken up. The dough is shaggy and looks wrong for about four minutes.
Knead eight minutes until the surface is smooth but the dough still feels like cold clay. Wrap it in film and rest 30 minutes at room temperature. If you skip the rest the sheet will recoil at notch 5 and the ribbons will curl into tubes as they dry.
The rolling sequence, and why 4 is skipped
Go 1 - 2 - 3, then jump to 5, then 6, then 7. Notch 4 adds nothing between 3.4 mm and 2.0 mm except another pass that warms the sheet; skipping it keeps the dough cold, which is the only thing standing between you and a sticky roller.
Dust with semolina, not with 00. Semolina grains are angular and roll out from under the sheet; 00 packs down and turns to glue in the rollers. Cut at notch 7 for a 1.2 mm sheet and a 6 mm ribbon.
Cooking and finishing
Use 1.5 litres of water per 100 g of pasta and salt it at 10 g per litre. Fresh egg tagliatelle needs three minutes, no more; at four minutes the yolk flavour flattens and the ribbon goes limp.
Pull the pasta out 30 seconds early and finish it in the ragù pan with 60 ml of the cooking water. The starch in that water is what binds the sauce to the ribbon, and it is the difference between tagliatelle al ragù and noodles with sauce on top.