Guscioni, so called for their form of large shell, are that of the piadine stuffed in various ways, not to be confused with the artusian watercress.
Tradition wants them to be filled with potatoes, pumpkin, chard, spinach or other field herbs, sautéed in a pan with garlic and oil. Their version with herbal filling is also served fried.
Mix the flour with the butter, salt, water and a teaspoon of baking soda, so how do I use to get the typical piadina romagnola. Let it sit for about a half hour.
Then roll the dough into thin discs and put on half of each disc, the herbs previously sautéed. Fold the dough over itself tessa until a Crescent and seal the edges with the tines of a fork.
Bake in a hot frying pan or on a griddle for about a couple of minutes on each side.