Icecream

Make the roasted Jerusalem artichoke ice cream: Preheat the oven to 350°F (175°C). In a hotel pan, toss the sliced Jerusalem artichokes with half the sugar. Roast until the slices are nice and golden.
Don't worry if the sugar starts to caramelize on the bottom of the pan— you want that to happen. Remove the pan from the oven, pour the cream and milk over the mixture and then return the pan to the oven for an additional 10-15 minutes.
Remove the pan from the oven and scrape the bottom of the pan, then let cool down.
When the mixture has cooled, strain it through a chinois, pressing out as much liquid as possible.
Slowly bring the temperature of your liquid up to scald cream.
In a heat-resistant bowl, whisk the yolks and remaining sugar until the mixture is pale and thick.
Pour one-third of the hot liquid into the yolk mixture and whisk to temper the egg yolks. Pour everything back in the milk-and-cream blend and quickly whisk it all together.
Switch to a spatula and continue to heat over medium-low heat for about 8-10 minutes, constantly stirring and making sure to scrape the bottom of the pot, until the mixture coats the spatula (160°F/71°C).
Strain the custard into a clean bowl and put the bowl in an ice bath. Refrigerate overnight, then churn according to your ice cream machine's instructions.

Candied Jerusalem Artichoke Skins

Preheat the oven to 170°C (340°F). Place the Jerusalem artichokes directly on the oven racks and bake until completely soft, 1 to 1½ hours. Transfer the Jerusalem artichokes to a sealed container and allow to steam for 30 minutes.
Cut each Jerusalem artichoke in half and scrape out the flesh, reserving it for another use. Mix the water with the sugar, then dip the Jerusalem artichoke skins in the sugar syrup.
Decrease the oven temperature to 150°C (300°F), place the glazed skins directly on the oven racks, and bake until golden brown, 25 to 30 minutes. Remove the skins from the oven and allow to cool on the rack at room temperature. They should become crispy.