Well, if you're an incompetent cook, a lot. Well, maybe not a lot, but enough. It's a custard ice cream, meaning that it contains eggs. And that the eggs have to be tempered. And I apparently couldn't temper eggs if my life. So after curdling the eggs, I decided to call it a day.
The next day, having regained my courage, I decided to try again, only without the eggs. I quickly found another recipe from a food-centric blog called Hungry in Hogtown, this time a non-custard with the Nutella swirled in. This looked even more idiot-proof than Giada De Laurentis's. Here are the details:
250 ml (1 cup) 35% heavy cream
250 ml (1 cup) 3.25% milk
1 vanilla bean or substitute vanilla extract
110 g (1/2 cup) sugar
120 g (1/3 cup) Nutella
10 ml (2 tsp) canola oil
Combine cream, milk, sugar, and scraped vanilla seeds and pod and heat to 175F/79C.
One hour before churning the ice cream, heat the Nutella in the top of a double boiler over barely simmering water. Stir in the oil, then remove from heat and allow to cool to room temperature.
Freeze ice cream as per maker's instructions. At the last moment, add the room temperature Nutella mixture to the ice cream. Do not overchurn after this point or the Nutella will incorporate into the ice cream, rather than forming a stripe.
I followed the recipe pretty closely, except I added probably a third more Nutella than it called for. If a little is good, a lot is better, right? I don't know what went wrong, but the Nutella-canola oil mixture never did form much of a swirl. Instead, it immediately broke up into tiny little grains of Nutella. Not particularly visually appealing, but still pretty tasty. I don't know if it was a function of the ice cream maker (I used a Cuisinart) or of the recipe, but it was exceptionally smooth and creamy. The whole vanilla bean also made for an intense vanilla flavor, with little bursts of Nutella. I thought that it was very tasty, although it would have been better if we could have waited long enough for it to freeze solid. I like it, but I owe it to Nutella to try, try again. Letitia thinks that it wouldn't be the best ice cream to use for making Nutella cookie ice cream sandwiches because the ice cream would overshadow the cookies. She's probably right.
(Incidentally, if you're looking for Nutella, you should look at Costco. They have a two pack of the 26.5 ounce bottles for a little over $8. The cheapest I have seen the 26.5 ounce bottle elsewhere is around $6. )