Melt the butter, and let's cool down. Set aside.
In a bowl, beat the eggs with a fork or a whisk, then add Parmigiano, semolina, baking powder, nutmeg, and salt. Stir.
Drizzle the melted butter, not too hot, over the batter and continue stirring until the mixture is soft and fluffy.
Choose a rectangular baking pan of 15x20cm or even smaller, line it with baking paper, or grease the bottom with butter or olive oil and pour the dough into the pan, spread evenly, and even out the surface with the help of a spatula.Kitchen note: the tray can be square or rectangular and never too small since Imperial Soup is, at most, 1/2 cm high. In this case, cut in half horizontally to reduce the height of cubes. Bake in preheated oven, 170C degrees (338F), for about 15 minutes or until edges and surface are lightly browned.
Remove from oven and let cool.
Place Imperial Soup on a cutting board or clean surface and cut into small cubes about 1/2 cm wide and tall. The Imperial Soup cubes absorb the broth, so they tend to expand like little sponges. Keep it in mind when you cut.
Cook the Imperial Soup in the lightly salted hot broth for two minutes. Serve the soup hot.