Trentino — the spinach-bread dumpling tradition is shared across the Tyrolese-Italian Alpine arc. Strangolapreti as a preparation is specifically documented in Trentino (as distinct from the Venetian or Umbrian uses of the same name for a pasta shape).
Strangolapreti (priest-stranglers — the same name used for a pasta shape in other regions) in Trentino are a specific type of bread dumpling: smaller and more delicate than canederli, made with stale bread, spinach (or beet greens), egg, and a small amount of flour, shaped into rough oval quenelles and boiled in salted water. They are served dressed with melted butter and sage (burro e salvia — the Alpine preparation for all pasta in brodo or dumplings) and a snowfall of aged Grana Padano or Trentino Grana. The spinach gives them a green colour and a slightly mineral flavour that distinguishes them from the meat-enriched canederlo.
Strangolapreti trentini are soft, slightly green, and smell of spinach, nutmeg, and stale bread — modest aromatics that are elevated by the brown butter and sage to something aromatic and satisfying. The Grana Trentino adds the necessary salt and sharp dairy note. It is one of the quietest preparations in Italian cooking, and one of the most satisfying in cold weather.
Stale white bread (cubed, soaked in milk, squeezed dry — the same preparation as canederli). Spinach blanched, squeezed completely dry, and finely chopped (any excess moisture will destabilise the dumplings). Mix the bread, spinach, eggs, salt, nutmeg, and enough flour to bind (typically 2-3 tablespoons per 500g base). The mixture should hold a rough shape when pressed but should not be rolled into perfect spheres — the irregular quenelle shape is traditional. Test-poach one before shaping the batch. Simmer (not boil) in salted water for 8-10 minutes. Dress immediately with brown butter and fried sage leaves.
The brown butter (burro fuso) technique: melt butter slowly until the milk solids turn golden-brown and the butter smells of hazelnut — not burnt. Add fresh sage leaves in the last 30 seconds — they crisp in the butter. Pour over the strangolapreti immediately. The combination of spinach dumplings, brown butter, sage, and aged cheese is one of the paradigm flavour combinations of Alpine Italian cooking.
Spinach not dry enough — the water in insufficiently drained spinach makes the mixture too wet, causing disintegration during poaching. Adding too much flour — over-flouring produces dense, floury dumplings; the minimum flour that achieves binding is the correct amount. Vigorous boil — a rolling boil breaks up the delicate dumplings.
Slow Food Editore, Trentino-Alto Adige in Cucina; Elizabeth David, Italian Food