Even sardine skeptics will enjoy this lemony pasta with crispy breadcrumbs. Substitute two 5-to 6-ounce cans chunk light tuna for the sardines if you prefer. If you are using tuna or can't find sardines packed in tomato sauce, add 2 tablespoons tomato paste in step 4 with the lemon juice. Serve with a salad of bitter greens tossed with a lemon vinaigrette and a glass of pinot grigio.