- 3 navel oranges
- 5 tablespoons sugar
- 1/2 cup English-style bitter orange marmalade
- 2 cups half-and-half
- 1 cup heavy cream
- 5 large egg yolks
- 1/2 teaspoon vanilla extract
- 1/8 teaspoon almond extract
- 1/4 teaspoon salt
- Vegetable oil for pan
- 1 cup slivered blanched almonds (4 1/2 oz)
- 1/2 cup sugar
- 3 1/2 tablespoons unsalted butter, softened
- 2 tablespoons light corn syrup
- 2 tablespoons heavy cream
- 1/4 teaspoon vanilla extract
- 1/8 teaspoon salt
- 2 teaspoons all-purpose flour
- 5 oz fine-quality bittersweet chocolate (not unsweetened), finely chopped
- Special equipment: an instant-read thermometer; an ice cream maker; parchment paper; a 2 1/2-inch fluted round cookie cutter; a pastry brush: an offset metal spatula
- Finely grate zest from 2 oranges and cover zest with plastic wrap. Squeeze enough juice from all 3 oranges to measure 1 1/2 cups. Bring juice and 3 tablespoons sugar to a boil in a 1-quart saucepan and simmer until reduced to about 3/4 cup, about 10 minutes. Add marmalade and simmer, stirring, until melted, about 1 minute. Remove from heat and cool.
- Bring half-and-half, cream, remaining 2 tablespoons sugar, and grated zest to a boil in a 2-quart heavy saucepan, stirring until sugar is dissolved. Whisk yolks in a bowl until blended, then add 1/2 cup hot cream mixture in a slow stream, whisking. Stir custard into cream mixture in saucepan and cook over moderately low heat, stirring constantly with a wooden spoon, until thick enough to coat back of spoon and registers 175 to 180°F on thermometer (do not let boil).
- Pour custard through a fine-mesh sieve into a (clean) metal bowl and stir in marmalade mixture, vanilla, almond extract, and salt. Cool to room temperature, stirring occasionally, then chill, covered, until cold, at least 2 hours.
- Freeze custard in ice cream maker. While ice cream is freezing, oil bottom and sides of a 13- by 9-inch baking pan, then line bottom lengthwise with a sheet of plastic wrap, leaving a 2-inch overhang on each short end. Spread ice cream in pan, smoothing top, then wrap pan in plastic wrap and freeze until ice cream is hardened, about 4 hours.
- Put oven rack in middle position and preheat oven to 350°F. Line 2 baking sheets with parchment.
- Pulse almonds with sugar in a food processor until finely ground. Cook almond mixture, butter, corn syrup, cream, vanilla, and salt in cleaned 1-quart saucepan over moderate heat, stirring until butter is melted and sugar is dissolved, 2 minutes. Remove from heat and stir in flour, then transfer batter to a bowl and chill until firm, about 1 hour.
- Roll level teaspoons of batter into balls and arrange about 3 inches apart on baking sheets. Gently flatten balls to about 1 1/4 inches in diameter with a fingertip.
- Bake cookies in batches until golden brown, 7 to 9 minutes. Slide parchment with cookies from sheet onto a rack to cool completely.
- Melt chocolate in a double boiler or a metal bowl set over a saucepan of barely simmering water, stirring occasionally, then remove top of double boiler or bowl from heat.
- Working with 1 cookie at a time, lightly brush undersides of cookies with chocolate and put, chocolate sides up, on rack. Chill cookies in 1 layer until chocolate sets, about 5 minutes.
- Unwrap pan of ice cream and cut out 12 (2 1/2-inch) ice cream rounds with cookie cutter. Lift out rounds with offset spatula and sandwich each between 2 chilled florentines, chocolate sides in.