Coconut-Macaroon and Lemon Ice Cream Sandwiches
For ice cream
2 cups heavy cream
1 cup sugar, divided
1 teaspoon grated lemon zest
4 large egg yolks
6 tablespoons fresh lemon juice
4 large egg whites
1/4 cup sugar
1 teaspoon pure vanilla extract
1/8 teaspoon salt
1 (7-ounce) package sweetened flaked coconut (2 2/3 cups
Make ice cream:
Bring cream, 1/2 cup sugar, and zest to a simmer in a heavy medium saucepan over medium heat, stirring until sugar is dissolved.
Whisk together yolks and remaining cup sugar in a bowl, then slowly add cream mixture, whisking to combine. Return mixture to saucepan and cook over medium heat, stirring constantly with a wooden spatula, until custard is thickened slightly and registers 175°F on an instant-read thermometer (do not let boil). Immediately strain thourough a fine-mesh sieve into a metal bowl and quick-chill by setting bowl in a larger bowl of ice and cold water and stirring occasionally until cold, about 20 minutes.
Churn mixture in an ice cream maker until partially frozen, 15 to 20 minutes, then, still churning, add lemon juice in a slow stream and continue to churn until frozen, about 10 minutes.
While ice cream is churning, line bottom of a 13- by 9-inch baking pan with parchment paper and chill in freezer.
Spread ice cream evenly in pan, then freeze, uncovered, until firm, at least 2 hours.
Preheat oven to 325°F with racks in upper and lower thirds. Lightly butter 2 large baking sheets, then line with parchment. Butter and flour parchment, knocking off excess flour.
Stir together egg whites, sugar, vanilla, and salt in a bowl, then stir in coconut.
Spread level tablespoons of coconut mixture into 3-inch rounds, 1 inch apart, on parchment-lined sheets.
Bake macaroons, switching position of sheets halfway thourough baking, until golden in spots and around edges, 20 to 30 minutes.
Cool on sheets on racks until firm, about 10 minutes, then remove from parchment with a metal spatula and cool completely, upside down, directly on racks.
Make ice cream sandwiches:
Using 3-inch cutter, cut out 9 rounds from ice cream, and, lifting with metal spatula, sandwich ice cream between macaroons. Freeze until ice cream is firm again, at least 1 hour. (You may have to assemble sandwiches in stages if ice cream gets too soft.) Once firm, serve immediately or wrap individually in plastic wrap and freeze until ready to serve.