PreparationMake ice cream: Have ready a large bowl of ice and cold water. In a saucepan bring cream and milk just to a boil. In a small bowl with an electric mixer beat together eggs and sugar until thick and pale. Add 1 cup hot cream mixture to egg mixture in a slow stream, whisking. Whisk egg mixture into cream mixture in pan and cook over moderate heat, stirring constantly, until thickened slightly, just coats back of spoon, and a candy thermometer registers 170° F. (Do not let custard boil or it will curdle.) Pour custard through a fine sieve into a bowl set in bowl of ice water and stir in elderflower concentrate (or vanilla mixture; see above note). Cool custard. Chill custard, its surface covered with plastic wrap, at least 1 hour and up to 24. Freeze custard in an ice-cream maker. Transfer ice cream to an airtight container and in freezer harden until firm. Ice cream may be made 1 week ahead. Make sorbet: In a saucepan bring sugar and water to a boil, stirring until sugar is dissolved. Stir in strawberries and lemon juice and cool 10 minutes. In a food processor purée mixture until very smooth and force through a sieve into a bowl, pressing hard on solids. Discard solids and cool purée. Freeze purée in an ice-cream maker. Transfer sorbet to an airtight container and in freezer harden until firm. Sorbet may be made 1 week ahead. Assemble bombe: Let ice cream and sorbet stand at room temperature until softened, about 10 minutes. Into a large bowl scoop alternating cup measures of ice cream and sorbet. Make 2 figure-eight swirls with a large metal spoon through ice cream and sorbet and pour into a 7- to 8-cup mold. Freeze bombe, covered with plastic wrap, at least 4 hours and up to 2 weeks. To unmold bombe, dip mold in a bowl of hot water 1 second and invert bombe onto a serving plate. Garnish bombe with strawberries.
PreparationMake ice cream: Have ready a large bowl of ice and cold water. In a saucepan bring cream and milk just to a boil. In a small bowl with an electric mixer beat together eggs and sugar until thick and pale. Add 1 cup hot cream mixture to egg mixture in a slow stream, whisking. Whisk egg mixture into cream mixture in pan and cook over moderate heat, stirring constantly, until thickened slightly, just coats back of spoon, and a candy thermometer registers 170° F. (Do not let custard boil or it will curdle.) Pour custard through a fine sieve into a bowl set in bowl of ice water and stir in elderflower concentrate (or vanilla mixture; see above note). Cool custard. Chill custard, its surface covered with plastic wrap, at least 1 hour and up to 24. Freeze custard in an ice-cream maker. Transfer ice cream to an airtight container and in freezer harden until firm. Ice cream may be made 1 week ahead. Make sorbet: In a saucepan bring sugar and water to a boil, stirring until sugar is dissolved. Stir in strawberries and lemon juice and cool 10 minutes. In a food processor purée mixture until very smooth and force through a sieve into a bowl, pressing hard on solids. Discard solids and cool purée. Freeze purée in an ice-cream maker. Transfer sorbet to an airtight container and in freezer harden until firm. Sorbet may be made 1 week ahead. Assemble bombe: Let ice cream and sorbet stand at room temperature until softened, about 10 minutes. Into a large bowl scoop alternating cup measures of ice cream and sorbet. Make 2 figure-eight swirls with a large metal spoon through ice cream and sorbet and pour into a 7- to 8-cup mold. Freeze bombe, covered with plastic wrap, at least 4 hours and up to 2 weeks. To unmold bombe, dip mold in a bowl of hot water 1 second and invert bombe onto a serving plate. Garnish bombe with strawberries.