Boil citrus zest and juice with 500ml water for 10 minutes then add carrots and spices to reduce into a thick marmalade.
Sous vide celeriac and carrots separately with sugar at 90°C for two hours until tender.
Whisk milk, cream, egg yolks, sugar, and vanilla together to create a custard base and split into two halves.
Heat half of the custard over medium heat until thickened then chill over an ice bath.
Cook celeriac with milk until soft and blend into a smooth purée.
Combine the purée with cooled custard and churn in an ice cream machine until frozen.
Place marmalade and candied vegetables into the bottom of eight 7cm heatproof dishes.
Top with buttered brioche discs and the reserved custard then refrigerate for two hours.
Preheat the oven to 110°C.
Bake the puddings in a water bath for 45 minutes until the custard sets.
Caramelise the sugar on top with a blow torch and serve with celeriac ice cream.