Bostrengo is a traditional cake hailing from the region of Marche. There are 22 different versions of the cake with slight modifications, and it's also known as frustenga or fristingo in some parts of Marche. The cake is usually made with a combination of rice, eggs, lemon zest, pine nuts, chocolate, coffee, dried figs, rum, and confectioners' sugar.

The rice is cooked in water or milk with sugar, grated zest, raisins, pine nuts, eggs, coffee, grated chocolate, and rum. The mixture is placed into a baking dish, and it's then baked until a golden crust forms. Once done, bostrengo is cut into wedges and served dusted with powdered sugar.