My parents have a cabin in the mountains in Colorado, where they have a neighbor who is officially a Mountain Man, with a long scraggly beard, horses running around on his property, and the requisite amount of woman trouble. One day the Mountain Man and I got to talking about pie. He declared that pie is simple – it’s a mixture of fruit, flour, and sugar baked in a crust. I don’t recall whether we discussed his crust recipe, but I have to believe it comes from a vacuum-packed tube.
While I can agree that fruit pies are, at their most basic, a mixture of fruit, sugar, and thickener, I would disagree that that makes them simple. In fact, it makes them particularly tricky. First, the best thickener for each fruit varies – is it flour, cornstarch, tapioca, or something impossible to find in the average grocery store? Second, and worse, is that the perfect amount of thickener will vary depending on how ripe the fruit is. Exceptionally juicy peaches will need more thickener (and less sugar) than just barely ripe peaches.
I’ve gotten strawberry rhubarb pie wrong at least as often as I’ve gotten it right. Cook’s Illustrated has a recipe for it that starts with sautéing the rhubarb with sugar to get rid of some of the excess liquid. I did make an awesome pie with this recipe, but it resulted in the worst burn I’ve ever had when a chunk of super hot sugar-coated rhubarb landed on my foot. Plus it’s a hassle – who wants to deal with pre-cooking the filling in addition to rolling out dough and chopping filling ingredients?
I tried Deb’s recipe last year, which calls for tapioca as the thickener, but didn’t like the bits of gelatinous tapioca mixed with the fruit filling. I thought the answer was grinding the tapioca to a powder with a spice grinder (aka repurposed coffee grinder) until I saw Cook’s Illustrated comment (in The New Best Recipe) that tapioca and rhubarb don’t make a great pair. I happen to have arrowroot powder in the cabinet, so I used that instead.
And what I got was a perfect strawberry rhubarb pie. When the first slice was removed, the filling didn’t flow in to fill the void, but it wasn’t dry. It was just sweet enough. I didn’t use flour in the filling, but I still think that even Mountain Man would approve.
I used Deb’s recipe for pie crust.
If you can’t find arrowroot powder, use ¼ cup of tapioca, ground in a spice grinder.
Baking the pie on a baking sheet catches any drips; preheating the baking sheet helps the bottom crust become crisp and flaky instead of soggy.
dough for a double-crust pie, rolled into two 13-inch circles and refrigerated
½ cup + 2 tablespoons (4.4 ounces) granulated sugar
¼ cup (1.75 ounces) light brown sugar
¼ cup arrowroot powder
¼ teaspoon salt
24 ounces (about 3½ cups) rhubarb, sliced ½-inch thick
16 ounces (about 3½ cups) strawberries, hulled and sliced if big, halved if small
1 tablespoon lemon juice
1 tablespoon unsalted butter, cut into small pieces
1 egg beaten to blend with ¼ teaspoon salt (for glaze)
1. Place a rimmed baking sheet on the middle rack of the oven; heat the oven to 400 degrees.
2. In a large bowl, mix the sugars, arrowroot powder, and salt. Add the rhubarb, strawberries, and lemon juice; stir to combine well.
3. Line a 9-inch pie plate with one round of dough. Transfer the filling to the lined pan. Scatter pieces of butter over the fruit. Top with the second round of dough, sealing and fluting the edges. Cut 8 slits in the top crust and brush with the egg wash.
4. Transfer the pie to the hot baking sheet. Bake for 20 minutes, then reduce the oven temperature to 350 degrees; bake for an additional 25 to 30 minutes, or until the top crust is golden brown and the filling is bubbly.
5. Transfer the pie to a wire rack and cool at least 4 hours before serving.