
We call for English-style bitter orange marmalade (made with Seville oranges and often called Dundee) because other types made the ice cream too sweet and too soft. It's available at specialty foods shops and some supermarkets. This recipe makes about a dozen more florentines than you'll need for the sandwiches, but it's a good idea to have extra in case one or two break — and the cookies are delicious even without the ice cream.
Active time: 1 1/2 hr Start to finish: 7 hr (includes freezing)
Florentine cookies (brushed with chocolate but not filled with ice cream) can be made 2 days ahead and chilled, layered between sheets of wax paper, in an airtight container. Ice cream sandwiches can be assembled 3 days ahead and frozen, individually wrapped well in plastic wrap. Let soften in refrigerator 5 to 10 minutes before serving.