Here’s a colorful dish of marinated shrimp served with a luscious fruity orange and shallot sauce, accompanied by a mound of burnished radicchio and a few drops of your best balsamic vinegar.

My recipe is based on a dish served at the restaurant Franco Rossi in Bologna. The chef confided his personal secret: a white paste composed of shallots ground with butter and olive oil to thicken the sauce.