LEMONGRASS ICE CREAM

Steps:

• For the Dehydrated Grapefruit
• Heat the oven to 150°F. Line a baking sheet with a Silpat or parchment.
• Cut off the top and bottom of each grapefruit with a thin, sharp knife, to the point where you expose the flesh. Set one cut end down on your work surface and cut off the peel and white pith. Just follow the shape of the fruit and then go back to trim off any bits of pith you've missed. Set a strainer over a bowl. Working over the strainer and holding the grapefruit in your hand, cut down next to one membrane, then up-along the other membrane that's holding the segment-and drop the segment into the strainer. Continue until you've freed all the segments.
• Toss the grapefruit segments in sugar, carefully, so you don't break them. Shake off the excess.
• Arrange the grapefruit segments on the baking sheet and dry in the oven until reduced by half in volume and just slightly moist and a bit sticky. Start checking at about 2 hours; drying time will depend on your oven and the moisture of the grapefruit. Alternatively, line dehydrator trays with acetate and spray with cooking spray. Set the dehydrator to 120°F. Arrange the grapefruit segments on the trays and dry for 6 hours. Store in a single layer in an airtight plastic container for up to 2 days.
• For the Carbonated Lime Curd
• Set up an ice bath in a large bowl.
• Whisk the egg yolks and sugar together in a heatproof bowl until light. Whisk in the lime juice and set the bowl over a saucepan of simmering water. Cook, whisking and stirring often, until the curd reaches 180°F.
• Meanwhile, put the 2 tablespoons water in a small bowl and sprinkle the gelatin over the surface. Let sit for at least 1 minute, then microwave for 30 seconds or heat gently in a small saucepan until melted. When the curd has reached 180°F, stir in the gelatin.
• Strain into a medium bowl and mix with an immersion blender. Set into the ice bath to chill completely, then pour into a soda siphon, filling it two-thirds full (to leave room for the gasses). Screw on the top of the siphon and charge the curd with two cream whipper chargers (N2O) and one soda charger (CO2), shaking vigorously for at least 1 minute after each charge. Refrigerate until you're ready to serve or for up to 3 days.
• To Serve
• Layer the ice cream and grapefruit segments in the glass of your choice.
• Cut the tangerine sticks into short lengths and stick several in the glasses. Shake the siphon and top with a squirt of the lime curd.
• make it simpler
• You could make Tangerine Meringues (page 117) instead of the sticks.