Blanch the spinach in boiling salted water for 1 minute, drain, and plunge into cold water. Squeeze it dry with your hands and chop it finely.

In a mixing bowl, whisk the eggs, milk, chopped spinach, salt, and nutmeg together until evenly combined.

Add the flour gradually, beating with a wooden spoon until the batter is thick and smooth, and falls off the spoon in a slow ribbon rather than pouring.

Cover the bowl and rest the batter for 15 minutes at room temperature.

Bring a 6-quart / 5.7 L pot of salted water to a boil.

Working in batches so the pot doesn't overcrowd, press the batter through a spätzle maker or a wide-holed colander directly into the boiling water. Cook for 2 to 3 minutes until the spätzle float to the surface, then lift out with a slotted spoon and drain.

Heat a 12-inch / 30 cm skillet over medium heat. Add the diced speck and cook for 4 to 5 minutes until the fat renders and the edges crisp, then remove the speck with a slotted spoon, leaving the fat in the pan.

Add the butter and onion to the same skillet and cook for 3 to 4 minutes until the onion turns soft and translucent.

Add the sage leaves and cook for 30 seconds until fragrant.

Add the drained spätzle to the skillet and toss to coat. Cook for 3 to 4 minutes, stirring occasionally, until the dumplings pick up golden edges.

Return the crisp speck to the pan, toss, and season with black pepper. Add the grated Grana Padano and toss off the heat until it melts slightly into the butter.

Plate immediately, topping with extra grated cheese and a final crack of black pepper. Serve hot.