It's good! I wasn't sure what to expect but it works and I'd happily make it again. The alcohol doesn't taste as cooked-off as you might expect and if you like whiskey you'll probably like this dessert. I was wary of using all the sugar the recipe calls for but went ahead with it because I was afraid to change the texture, and thankfully it ended up being not particularly sweet. I meant to buy some crème fraiche to serve with it but forgot and it was tasty enough on its own. A dusting of powdered sugar might be nice on it, as would a scoop of good vanilla ice cream, or you could make it very festive with both of those plus more whiskey.
The recipe comes from here. I didn't make any major changes to it but I did make some notes in brackets.
Carrigaline Whiskey Pie (Sweet Whiskey and Potato Soufflé)
The source says this serves 6 but I think you can probably get at least 8 servings out of it. You'll want to have some leftover for breakfast, though, because it's nice and boozy the next morning and good with coffee. The texture changes as it spends time in the refrigerator — the first day mine had two layers, with the top one more cake-y and the bottom more moist, even though I baked it a bit longer than the recipe called for. A day or two later it was more uniformly like a cold soufflé. I think it's pleasant at every stage but let me know what you think.
A note about the almonds: the source calls for 3 almonds, pounded, period. I decided to use 3 tablespoons (ground rather finely in a food processor) because I've tried a few other cake recipes that call for 4 tablespoons and that seems to be about the right amount to do something for the texture without making the cake identifiably nutty. I didn't regret using the three tablespoons and I'm reasonably sure three almonds wouldn't do fuck-all except give you a squishy dessert.
1/2 lb boiled potatoes (approximately 1 1/4 cups) [I used German Butterball variety; any flavorful type that's not waxy ought to be ok]
1/4 lb butter, melted [I used Irish butter because I didn't want to make the leprechauns cry]
3/4 lb sugar
3 [tablespoons] pounded almonds
1 tablespoon orange extract or two tablespoons fresh bitter Seville orange juice [I used 2 tablespoons of marmalade]
6 eggs, separated
4 fluid ounces Irish whiskey
Butter and flour a 21-cm springform pan. Cut a piece of greaseproof paper / baking parchment to fit the bottom of the pan, butter it well, and put it in the pan. [I used a silicone springform pan with a ceramic bottom, buttered it well and skipped the parchment paper]. Alternately, if you don't have a springform pan, or just prefer to do it this way, prepare two 9-inch pie pans with a bottom crust only.
Preheat the oven to 375° F.
Mash the potatoes until smooth and lump-free. Separate the yolks and whites of the eggs. Beat the egg yolks until lemon-colored. Then beat in the sugar, adding it a little at a time until the mixture becomes fluffy.
Now beat in the potatoes. Once they're completely combined with the egg and sugar mixture, add the melted butter, pounded almonds, orange extract or orange juice [or marmalade, and finally the whiskey. Mix well: then pour into a large bowl and set aside.
Beat the egg whites until stiff, Carefully fold them into the egg mixture in the large bowl until they're completely incorporated. Make sure your oven is up to heat when you start this procedure.
When the egg whites are completely folded into the yolk mixture, pour immediately into the springform pan (or pie crusts) and put the pie(s) carefully into the oven. Close the oven door with as little vibration as possible, as any soufflé is vulnerable at this point.
Bake at 375° F for 40-45 minutes. Remove carefully from the oven and set aside to cool. The soufflés / pies will immediately fall at this point. This is normal, so don't panic! [Actually mine didn't fall much . . .].
The pie can be eaten while warm if you like, though (if you've made it in a springform pan, without crusts) it's somewhat fragile at this point and will tend to fall apart. You may prefer to let it cool to at least room temperature, or (better still) chill in the refrigerator overnight, after which it will slice a lot more easily.
Serve with unsweetened whipped cream or double cream, and perhaps with a grind of nutmeg on top. Serves approximately six. [No, eight, I think].