Trieste-Style Crab Gratin

All along the northeastern coast of Italy, there are delicious versions of this hot crab dip. I found my favorite in a minuscule candlelit trattoria nestled in the harbor of Trieste. Unlike American versions that include heavy doses of mayonnaise and cheese, Italians let the flavor of the main ingredient shine by pairing the crab with simple flavors—parsley, lemon, and, most notably, mashed potatoes. The use of potatoes in this hot dip may seem unusual, but they give the gratin a light, cre