Another tribute to Spain, where tuna croquettes are one of the most beloved tapas. ‘Nduja does turn this preparation in a Calabrian-Spanish specialty!
In a large pot gently melt the butter, avoiding browning; incorporate flour, carefully stir at very-low heat up to obtaining a sticky but uniform dough. Raise the heat, always stirring, bring to boil, then low the heat, add salt and keep on cooking until besciamella is thick enough. Turn off the heat, add well-drained and finely minced tuna.
Level besciamella on a flat surface and let sit for at least two hours.
Use wet hands to shape croquettes, roll them in breadcrumbs, then in beaten eggs and in breadcrumbs again. Fry croquettes in a pan with very hot oil.