Bring 3 cups water to a boil. Add a pinch of salt and the spinach.

Lower the heat and simmer, uncovered, until the spinach is bright green and tender, 3 to 4 minutes. Taste for salt and add more as needed. Remember that the pecorino is salty.

Remove from heat and pour the beaten eggs into the soup in a thin stream, whisking constantly. The eggs will form strands.

Place the bread slices in shallow soup bowls. Ladle the soup over the top and sprinkle with pecorino. Let rest a moment before serving so the bread can absorb some broth.