Happy 3.14, everyone!
For ScienceBlogs’ Pi Day competition, I’ve whipped up a pie that I’m calling “Citric Acid in your Eye Pi”.
Last year’s contest winner involved bacon, and I had no wish to be a copycat, so I’ve steered clear of meat entirely (because let’s face it: bacon is pretty unbeatable, so doing some other meat would just be begging for only second place). Instead I chose to do a pie involving my arch nemesis: whipped eggs. Custards and meringues have always posed a great problem for me, because no matter how many tips and tricks I learn, no matter how long I chill the bowl and the beater, and no matter how sure I am that there’s not a single drop of yolk or fat in the mix, there’s a 50/50 chance that my eggs just won’t ever reach stiff peaks. The reaction that makes simple egg whites turn into fluffy deliciousness is both fascinating and frustrating to me, and I love it. It also seemed appropriately scientific, considering that this contest is being done through ScienceBlogs.
Once it had been decided that custard was the order of the day, all that remained was to think of a flavour. Blueberries were suggested (they’re Kenneth’s favourite), but then another reaction came to mind: the curdling reaction of milk and acid. It’s always baffled me how lemon custard can manage to come out so sweet, without curdling into something completely disgusting, when the recipe involves both milk and lemon juice. I made a few alterations on an old-fashioned recipe, threw in a quote from The Simpsons (episode 2F22, Lemon of Troy), and voila! A pie was born, and my contest entry completed.
- 1 cup white sugar
- 1 tbsp butter (softened)
- 2 eggs, separated
- 1 cup milk
- 3 tbsp all-purpose flour
- 1/8 tsp salt
- 1/4 cup citrus* juice
- 2 tsp citrus* zest
* My original recipe just calls for lemon, but today I used a mix of lemon, lime and orange. You can use any and/or all of the above.
Start by building yourself a crust. Any type of pie crust will do, but today I used a chocolate crumble crust. Simply combine together 1-1/4 cups of chocolate cookie crumbs with 1/4 cup of melted butter, and press the mixture into the bottom of a 9-inch pie pan. Refrigerate the crust until the filling has been prepared.
To make the filling, combine the sugar and butter together until the butter is well mixed in. Then add the two egg yolks, and again mix well until the mix is relatively homogeneous. Next add the milk, flour and salt. This is easier if done in several additions, so that the flour doesn’t clump up. If you do end up with clumps of flour, use a fork or a whisk to break them up. Finally, add the citrus juice and zest. Set this mixture aside while you deal with the egg whites.
As I mentioned above, whipping up egg whites into a nice, frothy foam has always been a bit of a cooking challenge for me. Others continually inform me that it’s a very easy thing to do, but experience has taught me that there are many ways that it can go wrong. So here’s a few tips to help you out:
- Make sure that your bowl and whisk (or beaters, if you’re using a hand mixer) are VERY clean, and completely free of any oil or grease. The tiniest drop of oil in the mix will totally screw things up.
- Chill the bowl and whisk beforehand in the refrigerator. The cold will help. I use a metal bowl, but glass will work just as well (it just takes a bit longer to chill down).
- Don’t let any egg yolk get into your whites. If you’re not really confident in your egg-separating abilities, you can do each one separately into a smaller dish, and then pour all of your successful whites into your mixing bowl only once you’re sure that they’re yolk-free. If you screw up an egg or two, don’t worry: cover the dish with plastic wrap and set it aside in the fridge for tomorrow’s breakfast.
Once you’ve got your egg whites separated into your clean, cold bowl, get whisking. The egg whites will first become frothy, and then will start to stick together (and to your whisk). When you reach the stage known as “stiff peaks” — a consistency similar to whipped cream — you’ve had success, and you can stop whipping.
Fold your whipped egg whites into the rest of the custard mix, then pour the whole thing into your prepared pie shell. Then it’s into the oven at 325 degrees Fahrenheit for 50 minutes to an hour — a toothpick inserted in the center of the pie should come out clean.
For the chocolate decorations on top of this pie, I melted some semi-sweet chocolate chips together with a little bit of butter (about a cup of chocolate chip to a half-teaspoon of butter). The butter prevents the finished product from getting that white stuff on the outside. I then poured the melted chocolate into a Ziplock baggie, and snipped off a tiny corner. Through that corner I could then pipe the chocolate designs out onto some waxed paper (always do a few extra pieces, just in case some break when you try to lift them up later). The chocolate then went into the fridge to harden and cool.
For the citrus slices, I simply sliced very thin pieces of lemon, lime, and orange. I then covered those slices with white sugar, and refrigerated them for a few hours to let them soak up the sweetness.
It’s very important to not put on your decorations until the pie has COMPLETELY cooled. Otherwise the chocolate will melt, and the citrus slices will sink into the custard. Be patient, and leave your pie in the fridge for an hour or two before attempting the decorations.