Tailor-made for this role is Pi Day. Created by physicist Larry Shaw in 1988, Pi day is celebrated on March 14th because the date represents the first three digits of the mathematical symbol pi and happens to be Albert Einstein’s birthday. Mr. Shaw was working at the Exploratorium, an interactive science museum in San Francisco, where the staff created a circular parade and served fruit pies to share the concept in a fun and kid-friendly way. It’s a cool story even though like Barbie, I think “math is hard!” The circumference of a circle is a useful tool for non-math brains, like artists and designers. And pi has intrigued math brains, thinkers, and philosophers since ancient Greek times partly because it is “an irrational, transcendental number, continuing to infinity.” Thank you history.com! Any reason, really, is a fine reason to bake more pie.
Research is always an interesting way to begin a project, especially if the research involves looking at lots and lots of cookbooks. Though it is truly revolutionary having recipes at your fingertips on the internet, there is a certain pleasure in opening a physical cookbook. The writer has had to think about the concepts and recipes intensely thus having time to really mull over their ideas. It’s reminiscent of listening to a record album instead of sampling various cuts from the same artist.
One of my favorite modern cookbook authors is Julie Richardson, a baker from Vermont, who now lives in Portland, Oregon. I first became familiar with her book, Vintage Cakes, (Ten Speed Press, 2012) which I loved so much that I purchased her book Rustic Fruit Desserts, (Chronicle Books, 2009.) I bake from Rustic Fruit Desserts quite a bit because the book is organized into seasons, and I like her slight twists on traditional recipes. I usually decide to make a fruit dessert because I am confronted with an overabundance of seasonal fruit.
In the “Winter” section, I found a recipe for Apple Custard Pie with Orange. Being early February, the orange tree was loaded with fruit and we also had a bowl of local Watsonville apples on the counter. While the pie was attractive, I found the flavor of orange peel in the pie off-putting, though my Dad quite liked the taste. I did like the custardy filling with the apples. I decided to mash up the custard-apple combination with a recipe I’d seen with buttermilk and whisky. A surprising and delicious pie, suitable for St. Paddy’s Day, was born. It is a grown-up kind of dessert, not too sweet, so I was still thinking about a more fun and indulgent pie.
Another flavor I’d been messing around with was vanilla malt, as in a malted milkshake or Malt-O-Meal, the hot cereal brand. I really like the old-fashioned flavor of malt though it is hard to describe. Malt is toasted barley, which certainly doesn’t scream “yummy dessert flavor” to anyone, yet it is yummy. It is also tantalizingly subtle so needs to be handled delicately and not overpowered by other strong flavors. Vanilla is a lovely foil to the earthiness of malt.
In the cookbook Handheld Pies by Sarah Billingsley and Rachel Wharton, (Chronicle Books, 2011,) I noticed a recipe for vanilla malt mini pies with a fun pretzel crust. I tested the recipe as a normal sized pie and was not happy with the results. The recipe did not successfully translate into a full-sized pie and was much too sweet for my taste. I rethought the whole recipe and traded the baked-in filling for a separate, pastry cream filling. I ended up changing almost everything about that recipe except the idea of a pie with a creamy, malt flavored filling, in a pretzel crust. I used David Lebovitz’s straight-forward pretzel crust recipe for my pie, just scaling the recipe down for a thinner crust. (I recommend looking at his other recipes here: https://www.davidlebovitz.com/ )
I’m really happy with the resulting pie. Testers loved the creaminess and delicate maltiness. The final pie recipe is slightly salty, very creamy, and not too sweet. The pretzel crust is baked like a graham cracker crust. Unique to the original mini pie recipe, very finely grated chocolate is sprinkled over the hot crust, melting the chocolate. It then cools, creating a barrier between the crisp crust and moist filling. The original recipe called for milk chocolate, but I changed it to white chocolate, wanting to keep the pie shades of cream and white.
If you’ve not made pastry cream before, don’t be afraid. Pastry cream is a thicker version of pudding, thickened with egg and cornstarch. This makes it very handy to have around for filling layer cakes, making trifle, or filling éclairs. While not difficult, the method for pastry cream is very time and temperature sensitive. It helps to read the recipe through several times and set up your work station close to the stove. Even if a bit of the egg gets overcooked or the mixture gets lumpy, any lumps will be strained out before chilling. Cornstarch is completely cooked after being boiled 1 minute. Since the hot mixture must be vigorously whisked without stopping, it can be difficult to tell just when the thick mixture is really at a boil. When it nears a boil, it will become harder to whisk, and large bubbles will pop slowly up from the bottom, like a hot mud pit in Yellowstone Park. Really.
Feel free to go wild when decorating the pie. This is one instance when more is more; you might have the kids help. Since the inspiration was a soda fountain treat, I decided to stick stripy paper straws in the pie to mimic a malted milkshake. And why not use whole pretzels to echo the pretzel crust? Maybe colored sprinkles? More white chocolate? Or all of the above. Partially crushed malt balls would be great. It’s in celebration of our friend pi, so why not?
Buttermilk Irish Whiskey Apple Pie
Serves 6 to 8
Special equipment: medium sized microwave-safe bowl, sieve or colander, hand or stand mixer, silicone scraper, 9” pie dish, preferably glass, and cooling rack
- 2-3 medium apples, cored, peeled and sliced, to make 2 cups, packed
- 3 tablespoons Irish whiskey, divided
- 1 tablespoon water
- 2 tablespoons butter, softened
- ½ cup firmly packed light brown sugar
- 1 tablespoon flour
- 1 egg yolk
- 2 eggs, at room temperature, well beaten
- 1 teaspoon vanilla
- ¾ cup buttermilk, full fat if available
- 1 unbaked 9” pie shell
- A few sprinkles ground mace or nutmeg, optional
- In medium sized microwave-safe bowl, place apple slices, 1 tablespoon whiskey and 1 tablespoon water. Cover and microwave on high for 2 minutes or until apples are softened. Drain in sieve and discard any liquid. Leave in sieve and set aside to cool to lukewarm.
- Meanwhile, in mixer bowl, beat softened butter with brown sugar, scraping bowl as needed. When butter and sugar are fully incorporated and no lumps remain, beat in flour. Scrape bowl and beat in egg yolk.
- Gradually beat in eggs, a little at a time. Stir in vanilla and 2 tablespoons whiskey. When mixture is smooth, gradually beat in buttermilk. Set aside
- Arrange cooled apple slices in bottom of pastry-lined pie dish. Pour buttermilk mixture over apple slices. Sprinkle mace or nutmeg over top, if desired. Carefully place in preheated oven. Bake for 30 to 35 minutes or until top of pie looks set and crust is golden brown. Cool completely on rack. Pie is best the day it is made but can be stored at room temperature, loosely covered, for up to 3 days.
Serving suggestion: use store-bought caramel sauce, thinned with whiskey to decorate the plate. Garnish with whipped cream.
Serves 8 to 10
Special equipment: blender or large food processor, silicone spatula, medium sized heavy-bottomed saucepan, whisk, hand or stand mixer, fine mesh sieve, 2 medium bowls, waxed paper or plastic wrap, 9” pie dish
Pastry cream filling:
- 3 cups whole milk, divided
- 1 cup malted milk powder, such as Carnation brand
- 4 eggs
- 1 egg yolk
- 1 cup sugar
- ½ cup plus 1/2 tablespoon cornstarch
- ¼ teaspoon salt
- 2 teaspoons vanilla
- 1 ¼ cups crushed pretzels
- 3 tablespoons sugar
- ½ cup (1 stick) butter, melted plus soft butter for greasing pan
- 2 ounces white chocolate* very finely chopped or grated
- 1 cup whipping cream, well chilled
- 2 tablespoons powdered sugar
- 1 teaspoon vanilla
Ideas for Garnish:
Crushed pretzels, mini pretzels, plain or dipped in white chocolate, colored sugar, roughly smashed malt balls, striped paper straws, cut to approximately 4”
- Pastry cream filling: In blender or large food processor, combine 1 cup cold milk and malted milk powder. Blend until smooth, scraping down sides with spatula. In heavy-bottomed saucepan, whisk together remaining 2 cups of milk and malted milk mixture. Set aside.
- In mixer bowl with whisk attachment, beat eggs, yolk, sugar, cornstarch, and salt, scraping down sides as needed. Beat on high speed for 3 minutes, until very thick. Set aside.
- Set up a fine mesh sieve over a medium bowl; have it ready next to the stove.
- Over medium heat, heat milk mixture until very hot, stirring often. (Steam will puff up around edges of pan.) With mixer on low, gradually add a little of the hot milk to egg mixture. When combined, pour egg mixture back into saucepan, whisking constantly. When mixture nears a boil, it will become very thick and large bubbles will pop slowly up from the bottom. When boiling, keep whisking for 1 minute then remove from the heat. Beat in the vanilla.
- Immediately scrape filling into prepared sieve, pressing mixture through with spatula. Discard any lumps. Press a sheet of waxed paper or plastic wrap directly onto surface so no skin forms. Chill until completely cold or up to 2 days.
- Pretzel crust: Preheat oven to 350 degrees F. In medium bowl, combine pretzel crumbs and 3 tablespoon sugar. Stir in melted butter until crumbs are moistened. Generously butter a 9” pie dish. Press in pretzel mixture on bottom and up sides. Bake pie shell for 8 to 10 minutes.
- Immediately sprinkle finely chopped white chocolate evenly over the bottom of crust. Cool completely before filling. The pie shell can be made one day ahead, loosely wrapped, at room temperature.
- Assemble pie: stir pastry cream to loosen. Spoon into prepared crust, smoothing top.
- Whip chilled cream to soft peaks. Beat in powdered sugar and vanilla. Continue beating until almost stiff. Spoon over pie filling, spreading with spatula in to soft mounds. The pie may be chilled at this point for up to 2 hours. Garnish just before serving.
- Garnish: pie can be garnished with additional crushed pretzels, mini pretzels, plain or dipped in white chocolate, colored sugar, roughly smashed malt balls, cut striped paper straws, or shaved white chocolate curls. Serve immediately. Chill any leftovers, well wrapped for up to 2 days. The crust will soften during storage but will still be delicious.
- A note on the white chocolate for the crust: I recommend a bar of good quality white chocolate such as Lindt or Ghirardelli. A bar will be easier to grate or chop finely than morsels or disks. The idea is to have a thin layer of white chocolate melted over the warm crust, then hardened, creating a yummy barrier between the crust and the filling, keeping the crust crisper longer. If the layer of white chocolate is too thick, it will be difficult to cut the pie into neat slices.
- Above, a photo of an earlier version of the recipe, here garnished with shaved white chocolate, whipped cream rosettes and pretzel sticks dipped in white chocolate. The pretzel sticks looked to me like lit matchsticks or candles. They would be a fun and Covid-safe version of birthday “candles” that don’t need to be blown out. They would be cute on all manner of birthday cakes or pies.