16 vanilla wafers, finely ground in a food processor
2 teaspoons finely grated fresh orange zest
2 teaspoons unsalted butter, melted and cooled
1 tablespoon light corn syrup
1 cup orange sorbet, slightly softened
1 cup nonfat vanilla frozen yogurt
Garnish: finely julienned fresh orange zest

Line a 7 1/2 x 3 1/2-inch loaf pan with a double layer of plastic wrap, allowing a few inches of overhang along sides.

Stir together cookie crumbs, orange zest, butter and corn syrup in a small bowl, then press into bottom of loaf pan. Spread sorbet evenly over crumb crust and freeze 30 minutes to harden.

While sorbet is freezing, slightly soften frozen yogurt. Spread evenly over sorbet and freeze, covered with plastic wrap, until firm, at least 2 hours.

Using plastic wrap as an aid, lift frozen cake out of pan, then peel off plastic. Let stand 5 minutes to soften, then cut crosswise into 4 slices.

Makes 4 servings.