Celebrating Pi Day with Rhubarb Maple Meringue Pie
Today we celebrate Pi Day! No, not Pie day, that is January 23rd and we were rather sad when we saw that we had missed that one.
“First and foremost, Pi Day is a celebration of the mathematical constant, π (pi), or 3.14159265359.” You can see that the first three numbers are the date that we celebrate it on, if you’re writing the date 3/14.
I know, I know, it’s math, and you are here for food. But! Don’t leave yet!
Thankfully many people have made the association between Pi and pies. If Pi is used to work out the diameter of a circle, it naturally lends itself to pies of all sorts. Not just the sweet variety, but pizza pies too! So many delicious circular foods to explore and 3.14 makes it all possible.
Pi Day was first celebrated on a large scale in 1988. Larry Shaw, a physicist who worked at the San Francisco Exploratorium at the time organized the event, bringing together both the public and museum staff. The assembled marched around the circular spaces of the museum and then tucked into a bunch of pies, according to a piece by Newsweek.
We’re joining in on the celebration with a recipe from The All American Desserts Book by Nancy Baggett for a delicious Maple Rhubarbe Meringue Pie. This sweet and tart mix makes a delicious combination no matter when you choose to share it.The mild, light meringue topping adds a slight sweetness, which helps balance the tang of the rhubarb and the richness of the pastry. And really, who’s to say that pi cannot be celebrated every time you bake a pie?
Ingredients List
Single crust All-Purpose Pie Pastry Dough
All purpose flour for dusting dough
Filling
4 ½ cups ½ to ¾ inch long pieces of rhubarb ( which is roughly 1 ½ to 1 ¾ pounds with the stalks trimmed)
¾ cup granulated sugar (divided)
1 ½ teaspoons fresh lime or lemon juice
¼ -⅓ cup orange juice if needed *
3 ½ tablespoons cornstarch
Pinch of salt
⅔ cup maple syrup, preferably light amber
2 large egg yolks
Meringue
4 large egg whites, completely free of yolk and at room temperature *
Generous ¼ teaspoon cream of tartar
Pinch of salt
¾ cup plus 2 tablespoons powdered sugar
½ teaspoon vanilla extract
Rolling Out The Pastry
Lightly grease a regular 9-inch pie plate or coat with nonstick spray.
If the dough is cold and stiff, let it warm up until slightly pliable but still cool to the touch. Generously dust it on both sides with flour.
Roll out the dough between large sheets of baking parchment into a 13 inch round. Occasionally check the underside of the dough during rolling and smooth out any wrinkles. Gently peel off the top sheet of paper, then pat it back into place.
Flip the dough: peel off the bottom sheet.
Center the round, dough side down, in the pie plate.
Gently peel off the remaining paper.
Smooth the dough into the plate and patch any tears, if necessary.
Using kitchen shears of a paring knife, trim the overhang to ¾ inch.
Fold the overhang under to form an edge that rests on the lip of the plate.
Finish by fluting with your fingers or pressing on the edge with the tines of fork.
Prick the pastry all over with a fork.
Loosely cover the pastry and place in the freezer for 15 minutes or in the refrigerator for at least 30 minutes and up to several hours
Baking the Pastry
Position a rack in the lower third of the oven and preheat to 400 degrees F.
Insert a large square of aluminum foil coated with the nonstick spray (or use non stick foil) oiled side down into the chilled shell, smoothing the foil over the bottom and sides and folding it out over the rim to cover the pastry.
Fill the foil with dried beans, spreading them so they extend up the plate sides.
Set the pie shell on a rimmed baking sheet.
Bake for 25 minutes.
Carefully remove the foil and beans from the shell.
Continue baking for 5-10 minutes longer, or until the shell is nicely browned all over.
If the edges brown too rapidly, cover with strips of foil (or a pie shield).
Transfer the pie shell to a wire rack to cool.
The pie shell will keep, covered at room temperature for up to 24 hours.
Mixing Up the Filling
In a large nonreactive saucepan, thoroughly stir together the rhubarb, ½ cup of the granulated sugar, and the lime juice.
Let stand, stirring once or twice for about ten minutes or until the sugar is mostly dissolved and the mixture looks wet.
Bring to a boil over medium high heat, stirring.
Cook, stirring until the rhubarb pieces exude some juice and just begin to soften but still hold their shape, about four minutes.
Remove from the heat and let cool for about ten minutes.
Put the rhubarb in a sieve set over a large glass measure.
Press down hard on the rhubarb to extract as much juice as possible.
You should have ½ to ¾ cup juice, necessary, and enough orange juice to yield ¾ cup.
Reposition the rack in the middle of the oven and preheat to 350 degrees F.
Rinse and dry the saucepan.
Put the remaining ¼ cup granulated sugar, the cornstarch and salt in the pan and whisk until well combined.
Add the rhubarb juice, whisking vigorously until the mixture is completely smooth.
Bring to boil over medium- high heat, whisking.
Lower the heat slightly and cook, whisking constantly until very thick, smooth and translucent, about 1 minute.
Remove from the heat.
Vigorously whisk in the maple syrup until the mixture is completely smooth.
In a small deep bowl, whisk the egg yolks until lightly blended.
Pouring slowly and whisking constantly, add about ¼ of the maple mixture to the yolks.
Add the yolk mixture to the saucepan, whisking.
Cook over medium high heat, stirring constantly and frequently scraping the pan bottom with a wooden spoon, until the mixture boils for a full 1 ½ minutes.
Do not undercook, or the filling may thin out later.
Stir the reserved rhubarb into the maple mixture.
Cook, stirring just until the rhubarb is piping hot: the filling will be fairly thick.
Cover and set aside.
Whipping Up The Meringue
In a completely grease free and dry large bowl, combine the egg whites, cream of tartar and salt.
Using a mixer on low speed with a whisk shaped beater if available, beat the mixture until frothy. Raise the speed to medium and continue beating until the mixture is smooth fluffy and opaque, but still too soft to hold peaks.
(Check by stopping and lifting the beater)
Immediately add the powdered sugar 2 tablespoons at a time, beating for about 20 seconds after each addition.
Add the vanilla.
Raise the speed to medium high and beat for 2 minutes, scraping down the sides of the bowl as needed.
Raise the speed to high and beat for about 1 minute longer or until the meringue is fluffy and stands in firm but not dry peaks.
Assembling the Pie
Turn out the hot filling into the pre-baked pastry shell.
Set the pie on a rimmed baking sheet.
Spread half the meringue over the filling, making sure the meringue touches the pastry all the way around.
Top with the remaining meringue, mounding it in the center.
Attractively swirl the meringue with a table knife or the back of a large spoon.
Time to Bake!
Bake for 12 to 17 minutes or until the meringue is evenly tinged with brown all over.
For even browning, rotate the pie from front to back after six minutes.
Transfer the pie to a wire rack.
Let cool for at least two hours and preferably three or four hours before chilling or covering to minimize any beading of the meringue.
The pie will keep, covered, at room temperature for up to twelve hours (some beading may occur after the first few hours) or refrigerated for up to 2 days. The crust will soften with longer storage. Let come to room temperature before serving.
Additional Notes
For the orange juice, make sure that you have it on hand, but don’t measure it out until you’ve seen if you need it or not.
For separating egg yolks and whites, check out this video here! It’s really easy this way, and you’re less likely to end up with a punctured egg yolk than if you did it using the shells. (Although if you can do it that way, go you!)
Rhubarb has a lot of juice that can make the bottom of the pie soggy and gross. The rhubarb is briefly boiled ahead of time with sugar to release those juice. That is then drained off, reduced down and cooked with the rest of the filling.
If you don’t want to fuss with making pastry dough, or prebaking one, you can always pick up a premade one at the supermarket.
So that’s our contribution to Pi Day! Let us know what some of your favorite pies are over on our Facebook page!
If you notice during this process (or before or after haha) that there are issues with your oven, reach out! We can send one of our technicians to come out to you based on your schedule and help get your oven back in tip top shape!