Instructions

• Make the celery juice: Put celery, lemongrass and ½ tsp celery seeds in a small pot and add water JUST until the greens are covered. Boil 35-40 minutes until celery is soft. Remove lemongrass and using an immersion or regular blender, puree. Strain through a fine mesh strainer and set aside. You should have about 2/3 c celery juice.
• Make the rhubarb compote: While the celery is cooking, make the rhubarb compote. Mix the rhubarb, sugar, mint and lemon juice in a bowl and let sit 5-10 minutes. Then pour into a small saucepan set over medium-low heat, cover and cook until rhubarb is tender, about 5 minutes. Remove from heat, set aside to cool and then cover and chill in fridge.
• Make the ice cream: Whisk together cream, milk, sugar, cornstarch, and salt in a 2 1/2- to 3-quart heavy saucepan. Bring to a boil over moderate heat, whisking occasionally, then boil, whisking, 2 minutes. Remove from heat and whisk in the celery juice and ¼ tsp of the toasted seeds. Transfer to a bowl and chill, uncovered, until cold, at least 1 hour. Sprinkle the remaining ¼ tsp toasted celery seeds over the rhubarb compote.
• Freeze the liquid celery ice cream in an ice cream maker, then transfer to an airtight container and put in freezer to harden, at least 2 hours.
• Serve with the rhubarb compote.