Mix the flour and salt in a bowl. Combine the eggs, egg yolks and oil, add to the flour and mix, knead into a smooth dough. Shape the dough into a ball, then leave to rest for approx. 30 mins. at room temperature under a bowl rinsed in hot water.
Heat the clarified butter in a frying pan. Brown the meat in batches for approx. 2 mins. per batch, remove from the pan, season. Place the spinach in the same pan, loosen any bits that have stuck to the pan, simmer for approx. 3 mins. until all the liquid has evaporated, leave to cool. Blitz the spinach, meat and rosemary in a food processor. Add the egg and cheese, blitz briefly, season. Transfer the mixture to a piping bag, cut a small opening.
On a lightly floured surface, roll out the dough in batches into a rectangle approx. 2 mm thick. Keep separating the dough from the work surface. Using a pastry wheel, cut the dough lengthwise into strips approx. 5 cm wide. Pipe the filling into hazelnut-sized portions at approx. 4 cm intervals on one side of the dough strips. Brush the other half of the pasta strips with a little egg white, fold over the filling, press the long edges together, squeezing out any trapped air. Using your thumb and forefinger, divide the individual agnolotti at approx. 2 cm intervals and separate using a pastry wheel. Place the agnolotti on a floured tea towel. Continue until all the dough and filling has been used.
To cook the agnolotti
Cook the agnolotti in just-boiling salted water for approx. 5 mins. per batch, drain. Heat the butter in a pan, fry the sage leaves until crispy. Add the agnolotti, mix and plate up.